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ENGINEERING PHYSICS LABORATORY MANUAL
Subject Code : 17CA55102
Regulation : R17
Class : I B.Tech I Semester (CSE &EEE)
I B.Tech II Semester (ECE &ME)
CHADALAWADA RAMANAMMA ENGINEERING COLLEGE (AUTONOMOUS)
Chadalawada Nagar, Renigunta Road, Tirupati – 517 506
Department of Freshman Engineering
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CHADALAWADA RAMANAMMA ENGINEERING COLLEGE (AUTONOMOUS)
Chadalawada Nagar, Renigunta Road, Tirupati – 517 506
Department of Freshman Engineering
Name
Reg.No.
Branch/Section
Academic year
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INDEX
S. No Name of the Experiment Page No
1 Determination of thickness of thin object using wedge method 6-15
2 Determination of wavelength different colors of given mercury source
using diffraction grating in normal incidence method 16-19
3 Determination wavelength of laser source using diffraction grating 20-22
4 Determination of particle size using diffraction 23-28
5 Determination of Numerical aperture, acceptance angle of an optical
fiber 29-31
6 Energy gap of a Semiconductor diode 32-34
7 Determination of radius of curvature of a Plano-convex lens by forming
Newton’s rings 35-36
8 Hall effect – Determination of mobility of charge carriers 37-40
9 B-H curve – Determination of hysteresis loss for a given magnetic
material 41-43
10 Determination of dispersive power of a prism 44-46
11 Study of CRO measurements 47-49
12 LED and LASER characteristics 50-52
13 Field along the axis of coil carrying current – Stewart Gee‘s method 53-55
14 Determination of Planck’s constant using LED 56-59
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Introduction
Engineering Physics is an experimental science. The main aim of engineering physics is to give fundamental
knowledge of science and technology for engineering students.
The study of Engineering Physics emphasizes the application of basic scientific principles to the design of
equipment, which includes electronic and electro-mechanical systems, for use in measurements,
communications, and data acquisition.
The theory that is presented in lectures has its origins in, and is validated by, experimental
measurement. The practical aspect of Physics is an integral part of the subject. The laboratory practicals take
place throughout the semester in parallel to the lectures.
They serve a number of purposes:
• It is an opportunity, as a student, to test theories by conducting meaningful scientific experiments.
• It is useful to enrich and deepen understanding of physical concepts presented in lectures.
• It is helpful to develop experimental techniques, in particular skills of data analysis, the understanding of
experimental uncertainty, and the development of graphical visualization of data.
Students are advised to thoroughly go through this manual rather than only topics mentioned in the syllabus
as practical aspects are the key to understanding and conceptual visualization of theoretical aspects covered
in the books.
Objectives: The objective of the laboratory is learning.
To measure the different wavelengths different colours.
To understand the role of optical fiber parameters and signal losses in communication.
To recognize the importance of energy gap in the study of conductivity and hall effect in a
semiconductor
To understand the applications of B H curve.
To acquire a practical knowledge of studying the crystal structure in terms of lattice constant.
To recognize the application of laser in finding the particle size and its role in diffraction studies.
To learn to synthesis of the nanomaterials and recognize its importance by knowing its nano particle
size and its impact on its properties.
Out comes:
To recognize the importance of optical phenomenon like Interference and diffraction.
To acquire the practical application knowledge of optical fiber, semiconductor, dieclectric and
magnetic materials, crystal structure and lasers by the study of their relative parameters.
To recognize the significant importance of nanomaterials in various engineering fields.
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Instructions to the students:
The following instructions must be followed by the students in their laboratory classes.
1. Students are expected to be punctual to the lab classes. If they are late, they will be considered absent
for that particular session.
2. Students should strictly maintain the dress code.
3. Students must bring their observation note, record note (completed with previous experiment) and
the calculator, scales, pencils to every lab class without fail.
4. Students are advised to come with full preparation for their lab sessions by
(i) Reading the detailed procedure of the experiment from the laboratory manual.
(ii) Completion of observation note book (i.e.) Aim, Apparatus required, Formula (with
description), least count calculation, diagrams and the tabular column should be written in
the observation note before entering into the laboratory.
5. Data entry in the observation note book must be by pen only.
6. Bring necessary graph papers for each of experiment. Learn to optimize on usage of graph papers.
7. Graphs should be neatly drawn with pencil. Always label graphs and the axes and display units.
8. If you finish early, spend the remaining time to complete the calculations and drawing graphs.
Students must get attestations immediately for their observed readings.
9. Students should complete their calculations for their experiments and get it corrected on the same
day of that experiment.
10. Students who miss observation, record note they have to do the experiment once again and get it
corrected.
11. Class assessment marks for each experiment is based only on their performance in the laboratory.
12. Record note has to be completed then and there and get corrected when the students are coming for
the next lab class.
13. Students must strictly maintain silence during lab classes.
14. If any of the students is absent for the lab class for genuine reasons, he/she will be permitted to do
the experiment during the repetition class only.
15. Students are advised to perform their experiments under safety care.
16. If any student is found causing damage to the lab equipments, he/she shall replace the same with a
new.
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CHADALAWADA RAMANAMMA ENGINEERING COLLEGE, TIRUPATI
(AUTONOMOUS)
Syllabus for (R17 Regulations)
ENGINEERING PHYSICS LABORATORY (17CA55102)
(Common to All Branches)
Any 10 of the following experiments has to be performed during the I year I/II semester
1. Determination of thickness of thin object using wedge method.
2. Determination of wavelength different colors of given mercury source using diffraction grating in
normal incidence method.
3. Determination wavelength of laser source using diffraction grating.
4. Determination of particle size using diffraction.
5. Determination of Numerical aperture, acceptance angle of an optical fiber.
6. Determination of radius of curvature of a Plano-convex lens by forming Newton’s rings.
7. Hall effect – Determination of mobility of charge carriers.
8. B-H curve – Determination of hysteresis loss for a given magnetic material.
9. Determination of dispersive power of a prism.
10. Energy gap of a Semiconductor diode.
11. Study of CRO measurements.
References:
1. Engineering Physics Practicals – NU Age Publishing House, Hyderabad.
2. Engineering Practical physics – Cengage Learning, Delhi
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Expt. No: Date:
EXPERIMENT – 1
TO FIND THIKNESS OF A THIN OBECT USING WEDGE METHOD
1.1 AIM:
To determine the thickness of a thin object or wire or hair by forming parallel fringes using wedge
method.
1.2 APPPRATUS:
S. No Equipment Range Type Quantity
1 Sodium vapor lamp - Standard 1
2 Traveling microscope - Standard 1
3 Thin wire or hair or small piece of
paper - Standard 1
4 Reading lens - Standard 1
5 Plane glass plates - Standard 2
1.3 FORMULA:
The Thickness of wire or hair can be found using the following formula.
t = λ L/2β cm
where, ‘λ’= Wavelength of light source (cm) .
‘L’ = Distance between wedge to hair (cm).
‘β’ = Fringe width (cm).
1.4 PROCEDURE:
a. The experimental arrangement for producing parallel fringes is as shown in fig (1).
b. Two plane glass plates are taken. They are cleaned thoroughly. They are held in contact at one
edge. At the opposite edge, a thin paper is inserted between the glass plates. The air-wedge is
formed between the lower surface of upper and upper surface of lower glass plate.
c. This set up is carefully kept on black paper and placed on the plat form of traveling microscope.
d. Arrange the glass plate B at an angle of 450 over the base set.
e. Switch on the monochromatic light source and it is focus on the Double convex lens (L1). This
sends parallel beam of light. This beam of light falls on the glass plate B at 450
f. The glass plate ‘B’ reflects a part of light towards the air film enclosed by the glass plates.
g. The microscope is adjusted and focused until the parallel fringes are formed.
h. Starting from one side coincide the cross wires tangential to the parallel fringes and note the
reading for every 5 fringes (0th, 5th, 10th, 15th, 20th, 25th ………… ).
i. Calculate the fringe width β.
j. Measure distance between wedge to hair (L) using the scale.
k. The thickness of wire is calculated by using the formula: t = λL/2β cm.
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Fig: Arrangement and formation of parallel fringes.
1.5 TABULAR COLUMN:
TABLE -1
Least count (L.C) of traveling microscope = 0.001 cm
S.No
Ring No.
Microscope readings
MSR
(a) cm VSC
VSCXLC
(b) cm T = (a+b) cm
1 0
2 5
3 10
4 15
5 20
6 25
TABLE -2
S.No
Fringe
Number
Microscope
Reading (A) cm
Fringe
Number
Microscope
Reading (B) cm
Fringe Width
5β = (A~ B) cm
1 0 5
2 5 10
3 10 15
4 15 20
5 20 25
Avg β = _______cm
β = _______cm
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1.6 PRECAUTIONS:
1. The microscope should move in one direction from left to the right or right to left, so he back lash
error is avoided
2. To achieve good accuracy in the measurement of l should be repeated twice or thrice.
3. The glass plate should be perfectly plane.
4. The wire should be uniform.
1.7 OBSERVATIONS:
1. The distance of the object from edge of the wedge L =---------- (cm),
2. Fringe width β=------------ (cm)
3. Wavelength of source λ =5893X10-8 cm
1.8 RESULT:
Thickness of the thin wire is determined by using Interference by parallel fringes is……………..cm.
1.9 PRELAB VIVA QUESTIONS:
1. What is Interference? What are the conditions for interference?
2. Explain constructive & Destructive interference.
3. What is meant by monochromatic source?
4. What is the wavelength of sodium vapour lamp?
5. Define Path difference& Phase difference and give relation b/w them.
6. If any light ray reflected by the denser medium, what happens to its phase?
1.10 POSTLAB VIVA QUESTIONS:
1. What is the least count of travelling microscope?
2. Why we get the fringes in the shape of parallel?
3. What is the principle of wedge method?
4. What is the application of wedge method?
5. What is thin film?
6. What are examples of natural thin films?
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Expt. No: Date:
EXPERIMENT – 2
TO FIND WAVELENGTHS OF DIFFERENT COLORS OF MERCURY SOURCE
USING DIFFRACTION GRATING – NORMAL INCIDENCE METHOD
1.1 AIM:
To determine the wavelengths of different colors of a given mercury vapor lamp by using the diffraction
grating in normal incidence position.
1.2 APPARTUS:
S. No Equipment Range Type Quantity
1 Mercury vapor lamp - Standard 1
2 Spectrometer - Standard 1
3 Diffraction grating 15,000LPI Standard 1
4 Reading lens - Standard 1
5 Spirit level - Standard 1
1.3 FORMULA:
The wavelengths of different colors of mercury vapor lamp can be found using the formula
λ = sinθ
Nn A0
where, θ is the diffraction angle.
1.4 PROCUDURE:
The usual initial adjustments of the spectrometer are done. The least count of the vernier of the
spectrometer is found.
1.4.1 Normal Incidence:
a. The slit of the spectrometer is illuminated with mercury vapor lamp.
b. The telescope is placed in line with the axis of the collimator and the direct image of the silt is
observed.
c. The slit is narrowed and the vertical cross wire is added to coincide with the center of the image of
the slit (T1 from fig a) the reading of one of the vernier is noted.
d. The prism table is clamped firmly and the telescope turned through 900 and fixed in position.(T2 in
fig ).
e. The grating is held with the rulings vertical and mounted in its holder on the prism table such that the
plane of the grating passes through the center of the table and the ruled surface towards the
collimator.
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f. The prism able is released and rotated until the image of the slit is seen in the telescoped by
reflection on the ruled sided of the grating.
g. The prism table is fixed after adjusting the point of intersection of the cross wires is on the image of
the slit.
h. Then the vernier table is released and rotated through exactly 450 from the position so that the ruled
side of the grating faces the collimator.
i. The vernier table is fixed in the position and the telescope is brought back to the direct reading
position. Now the light from the collimator strikes the grating normally.
1.4.2 Measurement of wavelength (λ):
a. The telescope is rotated so as to catch the first order directed image on one side, say on the left
(fig. b).
b. The point of intersection of the cross wires is set on the consider color line and its readings is
noted on both the vernier scales.
c. Similarly the reading corresponding to the remaining color lines is noted.
d. Then the telescope is turned to the side i.e., right side and similarly the readings corresponding to
color lines of the first order spectrum are noted.
e. Half the difference in the readings corresponding to any one line gives the angle of diffraction
(θ) for those lines in the first order spectrum.The number of lines per cm. of the grating (N) is
noted and the wavelength of the spectral line (λ) is found by the relation, λ = sinθ
Nn A0
.
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1.5 TABULAR COLUMN:
TABLE -1
Order of spectrum (n) =1
S .No Color
(Left Side) MSR VSC VSCXLC MSR+VSCXLC
1 Blue VA
VB
2 Green VA
VB
3 Yellow VA
VB
4 Red
VA
VB
TABLE -2
S.No Color
(Right Side) MSR VSC VSCXLC MSR+VSCXLC
1 Blue
VAI
VBI
2 Green
VAI
VBI
3 Yellow VA
I
VBI
4 Red
VAI
VBI
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TABLE -3
S.N
o. Colour
Readings of Spectrometer θ
λ = 𝐬𝐢𝐧𝛉
𝐍𝐧 A0
Left side 1st
order
Right side 1st
order
VA VA1
(𝐱𝟏)
VB VB1
(𝐱𝟐)
Mean
2θ=
(𝐗𝟏+𝐗𝟐)
𝟐
Left
VA
Right
VB
Left
VA1
Right
VB1
1 Blue
2 Green
3 Yellow
4 Red
1.6 OBSERVATIONS:
Number of lines per cm on the grating N = 2500 lines /inch
= 2500lines/ 2.54cm [1 inch =2.54 cm]
= 984.25 lines/ cm
1.7 PRECAUTIONS:
a. Always the grating should be held by the edges. The ruled surface should not be touched.
b. Light from the collimator should be uniformly incident on the entire surface of the grating.
c. Spectrometer readings should take perfectly.
1.8 RESULT:
The wavelengths of different colors in a given source of light are determined by using the diffraction
grating in the normal incidence position.
S.NO. Colour Experimental
Wavelengths( A0)
Standard
wavelengths( A0)
1 Violet 3800- 4800
2 Indigo 4200 - 4500
3 Blue 4500 - 4950
4 Green 4950 - 5700
5 Yellow 5700 - 5900
6 Orange 5900 - 6200
7 Red 6200-6900
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1.9 PRELAB VIVA QUESTIONS:
1. What is meant by diffraction of light?
2. What is grating?
3. How does the grating form diffraction images when monochromatic light falls normally on it?
4. What is the difference B/w diffraction & refraction?
5. What are the standard wavelengths for different colors?
1.10 PRELAB VIVA QUESTIONS:
1. What is a Grating element &how its value is calculated?
2. What is the formula to calculate ‘N’ on the grating?
3. What is the grating element in your experiment?
4. Is there any difference between the standard wavelengths and obtained wavelengths?
5. What is the least of spectrometer?
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Expt. No: Date:
EXPERIMENT – 3
TO FIND WAVELENGTH OF LASER SOURCE USING DIFFRACTION GRATING
1.1 AIM:
To determine wavelength of laser beam by using a diffraction grating.
1.2 APPRATUS:
S. No Equipment Range Type Quantity
1 Laser source (diode laser) - Standard 1
2 Diffraction grating 2,000LPI Standard 1
3 Optical bench - Standard 1
4 Meter graph - Standard 1
5 Meter scale - Standard 1
1.3 FORMULA:
The Wavelength of a laser λ= Sin θ
N n cm.
where,
θ = angle of diffraction
n = Order of the diffraction.
N = No. of lines on the grating per cm.
1.4 FIGURE:
Fig. 1 Experimental arrangement of a laser source -Diffraction grating.
1.5 PROCEDURE:
a. Arrange laser source, diffraction grating and screen rectilinearly at the same height on the
optical bench.
b. Keep the distance (D) between the grating the screen at fixed value (say 20cm).
c. Switch on the laser source then the laser beam incident normally on the surface of the grating.
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d. Then the laser gets diffracted from the ruled surface of the given grating and formed
diffraction pattern on the screen.
e. We can observe different diffraction orders of the bright spots on the screen on either side of
the central maximum.
f. Let the distance from the central maximum to diffracted spot on the left side is d1 and that on
the right side is d2.
g. The average of the d1 and d2 is d.
h. The wave length of the given source can be determined by using this formula.
i. Repeat the experiment values (D=30, 40, 50cm…) and note the corresponding “d” values for
different diffraction orders and tabulate the readings.
1.6 TABULAR COLUMN:
TABLE - 1
S.
No
Distance
between
grating and
screen
(D) cm
Order of
diffraction
Distance of the diffracted spot
from central spot from central
maxima (cm)
𝜃 =Tan-1(d
D)
λ=Sin θ
N n cm. Left
side
d1 cm
Right
side
d2 cm
Mean
(d=𝑑1+𝑑2
2)cm
1
n=1
n=2
2
n=1
n=2
3
n=1
n=2
1.7 OBSERVATIONS:
Number of lines per cm on the grating N = 2500 lines /inch
= 2500lines/ 2.54cm [1 inch =2.54 cm]
= 984.25 lines/ cm.
1.8 RESULT:
The wave length of the given source (λ) is ……………………
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1.9 PRELAB VIVA QUESTIONS:
1. What is laser? What are the characteristics of laser?
2. What are the differences of laser source and ordinary source?
3. What is diffraction?
4. What are the differences between interference and diffraction?
1.10 POSTLAB VIVA QUESTIONS:
1. What is the wavelength of diode laser?
2. Is the laser source is highly directional and intense?
3. Is the laser light is monochromatic?
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Expt. No: Date:
EXPERIMENT – 4
TO FIND SIZE OF A PARTICLE USING DIFFRACTION GRATING
1.1 AIM:
To determine the size of tiny particles (in lycopodium powder) using a diffraction grating.
1.2 APPRATUS:
S. No Equipment Range Type Quantity
1 Laser source (diode laser) - Standard 1
2 Glass plates - Standard 2
3 Lycopodium powder - Standard 1
4 Graph paper - Standard 1
5 Scale - Standard 1
1.3 FORMULA:
The Size of the particle is
𝒅 =𝟏.𝟐𝟐𝒏𝝀𝑫
𝒓 cm
Where,
λ = Wavelength of a laser light (cm),
D = Distance between glass plate and screen (cm),
r = Distance of the first dark fringe from the central maximum or radius of the
first dark fringe (cm) and
n = Order of diffraction
Fig: Experimental arrangement
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1.4 PROCEDURE:
1. Arrange the diode laser, collimating lens, glass plate containing marble powder and screen
rectilinearly on an optical bench at the same height.
2. Collimate the lens in front of the laser source such that the glass plate should be exactly at the focal
point of the collimating lens.
3. Switch on the laser source and allow the laser light to incident on the glass plate normally.
4. The laser light can be diffracted at the edges of the marble particles.
5. Then we can observe the diffraction pattern in the form of fringes with central maximum on the
screen.
6. Then adjust the distance between the glass plate and the screen such that the first dark fringe
coincides with the first ring on the screen.
7. Measure the distance of the first dark fringe from the central maximum and also the distance between
glass plate and screen.
8. The size of the particle can be found by using this formula. i.e.,d= 1.22 nλ D/ r cm.
9. Repeat the experiment for the first dark fringe to coincide with different circles on the screen and
note the corresponding “r” and ”D” values
10. The readings are tabulated as shows in the given table.
TABLE
S.No Distance
between particle
deposited glass
plate and the
screen D(cm)
Order of
diffraction
(n)
Radius of the first
dark fringe
r (cm)
𝒅 =𝟏.𝟐𝟐𝒏𝝀𝑫
𝒓 cm
1
n =1
n =2
2
n =1
n =2
3 n =1
n =2
4 n =1
n =2
Ave=………..cm
Observations:
Wave length of the laser λ= 6900x10-8 cm
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RESULT:
The size of the given particle (marble powder) is (d)= ……………cm
VIVA-VOCE QUESTIONS:
1. Define diffraction. What are conditions of diffraction
2. Define laser and what are the characteristics of laser?
3. What are the differences between interference and diffraction?
4. What is wavelength?
5. What is diffraction?
6. Define laser.
7. What are the characteristics of laser?
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Expt. No: Date:
EXPERIMENT – 5
8.
TO FIND NUMERICAL APERTURE AND ACCEPTANCE ANGLE OF
OPTICAL FIBER
1.1 AIM:
To determine the acceptance angle and numerical aperture of an optical fiber.
1.2 APPRATUS:
S. No Equipment Range Type Quantity
1 Fiber optic light source - Standard 1
2 Optical fiber cables - Standard 1
3 Numerical aperture jig - Standard 1
4 Optical bench - Standard 1
1.3 FORMULA:
Numerical aperture (N.A) = sin (θa) = 𝑾
√𝟒𝑳𝟐+W2
Acceptance angle (θa) = sin-1(NA)
where
θa → Acceptance angle in radian= S,
W → Diameter of the circular image in cm,
L→ Distance from the fibre end to circular image in cm.
1.4 THEORY
Numerical Aperture is defined as the light gathering capability of the fiber
Mathematically given by: NA= Sin θA
Fig : Numerical Aperture measurement.
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1.5 PROCEDURE
1. The experimental set up for N.A .measurement is shown in fig.
2. One end of optical fiber connected to the fiber optic light source and the other end of the fiber is
connected to the Numerical aperture jig through the connecter.
3. The A. C main is switched on. The light emitted by LED passes through the optical fiber cable
to the other end.
4. Now, we get illuminated circular patch on the screen.
5. A screen with concentric circles of known diameter is moved along the length of the NA jig to
0bserve the circular spreading of light intensity on the screen.
6. The screen adjusted such that, the first circle from the center of the screen is completely filled
with light. At this position, the distance (L) from the fiber end to the screen is noted on the NA
jig.
7. The experiment is repeated for the subsequent circles by adjusting the length L along NA jig
and the readings are noted in table (1). The diameter of the circles may be determined using a
traveling microscope.
8. Numerical aperture and acceptance angle of cable is found by using the formula.
TABLE
s.no Diameter of the
Circular image
‘w’cm
Distance from the fibre
end to circular image
‘L’ cm
(N.A) = sinθa
= 𝑾
√𝟒𝑳𝟐+𝐖𝟐
(θa) = sin-1(NA)
1 5mm= 0.5cm
2 10mm= 1cm
3 15mm=1.5cm
4 20mm=2cm
5 25mm=2.5cm
6 30mm=30cm
1.6 RESULT
Numerical aperture of given optical fibre = ………
Acceptance angle of the optical fibre = ………
VIVA-VOCE QUESTIONS
1. What is an optical fiber?
2. What is total internal reflection?
3. What is acceptance angle?
4. What are applications of optical fibers?
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Expt. No: Date:
EXPERIMENT – 6
9.
TO FIND RADIUS OF CURVATURE OF PLANO-CONVEX BY FORMING
NEWTON’S RINGS
1.1 AIM:
To observe Newton rings formed by the interference and to determine the radius of curvature of a plano-
convex lens.
1.2 APPRATUS:
S. No Equipment Range Type Quantity
1 Travelling microscope - Standard 1
2 Plano-convex lens - Standard 1
3 Sodium vapour lamp - Standard 1
4 Glass plates - Standard 2
5 Magnifying lens - Standard 1
1.3 FORMULA:
The Radius of curvature of given plano-convex Lens is given by
R = Dn
2 −Dm2
4 (n−m) λ cm
where λ = wavelength of sodium vapor lamp) = 5893A0 =5893x 10-8 cm
D2n =Diameter of nth Ring (cm)
D2m = Diameter of mth Ring (cm)
1.4 THEORY:
The phenomenon of Newton’s rings is an illustration of the interference of light waves reflected from
the opposite surfaces of a thin film of variable thickness. The two interfering beams, derived from a
monochromatic source satisfy the coherence condition for interference. Ring shaped fringes are
produced by the air film existing between a convex surface of a long focus plano-convex lens and a
plane of glass plate.
When a plano-convex lens of long focal length is placed on a plane glass plate, a thin film of air is
enclosed between the lower surface of the lens and upper surface of the glass plate. The thickness of the
air film is very small at the point of contact and gradually increases from the center outwards.
The fringes produced are concentric circles. With monochromatic light, bright and dark circular fringes
are produced in the air film. When viewed with the white light, the fringes are colored. A horizontal
beam of light falls on the glass plate at an angle of 450. The plate B reflects a part of incident light
towards the air film enclosed by the lens and plate. The reflected beam from the air film is viewed with a
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microscope. Interference takes place and dark and bright circular fringes are produced. This is due to the
interference between the light reflected at the lower surface of the lens and the upper surface of the plate.
1.5 PROCEDURE
Fig. 1 Experimental set up Fig. 2 formation Newton’s rings
1. The experimental arrangement for producing Newton rings is as shown in Fig 1.
2. Keep the convex surface of the lens (P) over the glass plate G and arrange glass plate G at an angle
of 450 over the base set (Fig 1).
3. Switch on the monochromatic light source and it is focus on the double convex lens (L). This sends
parallel beam of light. This beam of light falls on the glass plate G at 450.
4. The glass plate ‘G’ reflects a part of light towards the air film enclosed by the lens (P) and the glass
plate (E).
5. A part of the light is reflected by the curved surface of the lens and a part is transmitted which is
reflected back from the plane surface of the glass plate.
6. These reflected light rays superimpose with each other producing interference and forming
interference and forming interference patterns in the form of bright dark circular rings.
7. These rings are seen with a travelling microscope (M) focused on the air film.
8. Now move the microscope to focus on a dark ring (say, the 20th order dark ring) on left side from the
center. Set the cross wire tangential to one ring as shown in fig. Note down the microscope readings.
9. In the similar way cross wire setting at 14th, 12th ---- 2nd dark ring, the readings are noted. The
microscope is moved in the same direction to the other side of the ring and the readings are noted
corresponding to the 2nd, 4th, 8th, 10th, ---- 14th dark ring on right side.
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TABLE
S.No Ring No.
(n)
Microscope reading Diameter
Left side Right side
MSR
(a)
VSR
(b)
TR(cm)
A=(a+b)
MSR
(a)
VSC
(b)
TR(cm)
B=(a+b)
D(cm)
A~B
D2
(cm2)
1
0
2 5
3 10
4 15
5 20
6 25
7 30
Average: D2n - D
2m= …………. cm2
1.5 GRAPH
A graph is drawn with the number of rings on the x- axis and the square of the diameter of the ring (D2)
on the y-axis. The graph is straight line passing through the origin. Form the graph the values of Dm2 and
Dn2 corresponding to nth and mth rings are found. From the graph, the slope is calculated. After
evaluating the slope, radius of curvature
of Plano – Convex lens can be
calculated.
26 | P a g e
1.6 PRECAUTIONS
1. When circular rings are formed don’t disturb the total arrangement.
2. Microscope readings must take perfectly.
3. After completion of Experiment, we switch off the Na lamp Transformer. Otherwise, due to heat it
may breaks.
4. The Plano-convex lens should be of large radius of curvature.
5. The centre of the ring system should be a dark spot.
6. The microscope is always moved in the same direction to avoid back lash error.
1.7 RESULT
The radius of curvature of given plano – convex lens is found.
From the Experiment R = ________________________ cm.
From the Graph R = ________________________ cm.
VIVA-VOCE QUESTIONS
1. What is Interference? What are the conditions for interference?
2. Explain constructive & Destructive interference?
3. What is the least count of travelling microscope?
4. If we filled water between plane glass plate and the lens, what happen to the diameters of rings?
5. Define Path difference& Phase difference? Give relation between them?
6. If any light ray reflected by the denser medium, what happens to its phase?
7. Why we get the fringes in the shape of circles?
8. What is the principle of Newton rings?
9. What are the applications of Newton rings?
10. What is thin film?
11. What are examples of natural thin films?
27 | P a g e
Expt. No: Date:
EXPERIMENT – 7
10.
TO DETERMINE THE HALL COEFFICIENT, THE CONCENTRATION OF
THE MAJORITY CARRIERS, THE MOBILITY OF THE CHARGE CARRIERS
1.1 AIM:
The objectives of the experiment are
1) To determine the Hall coefficient
2) To determine the concentration of the majority carriers
3) To determine the mobility of the charge carriers
1.2 APPRATUS:
S. No Equipment Range Type Quantity
1 The extrinsic semiconductor
material - P- Type 1
2 constant current source - Standard 1
3 electro-magnets - Standard 1
4
volt meter having high input
impedance
- Standard 1
1.2 INTRODUCTION:
If magnetic field is applied among X-direction and current is applied along Y-direction , then the voltage
will be developed perpendicular to the both current and magnetic field direction i.e. in Z-direction .This
effect is known as Hall effect and developed voltage is called Hall voltage. The schematic demonstration of
Hall Effect is known in fig 1.
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1.3 THE0RY:
Take a p-type semiconductor wafer of thickness t and area of cross-section A. It carriers a current ‘I’ is acted
upon by a transverse magnetic field B. The magnetic field deflect carriers in a semiconductor wafer towards
the one of the faces leading to an accumulation of charge carriers. This will produce an electric field EH in a
direction which opposes the Lorentz force due to magnetic field. The electric field which builds will be
exactly balances the electric field. The potential difference VH arising due to EH is given by VH=BI/ ρet
Thus RH =1 / ρe ; RH =VH t / BI
Slope =ΔVH /ΔI
Slope =ΔVH /ΔB
Where B is the magnetic field
I is the current , VH is the Hall voltage . The ratio is known as Hall coefficient RH.
Thus RH1 = [ Slope * (t/B )]
RH2 = [ Slope * ( t / I )] . Hall coefficient (RH) is given by
RH=[ RH1 +RH2] /2 m3/c ------------------- (1)
If we know the thickness ‘t’ of the semiconductor wafer, the magnetic field B and by measuring the Hall
voltage VH produced in the wafer for given current I, the Hall coefficient RH can be determined with the
help of equation (3). If we know the Hall coefficient, the concentration of charge carriers in the material can
be determined with the help of equation (1) .
Majority carrier concentration
n (or) ρ = 1 / (RH *e ) ------------- (2)
Conductivity (σ) is given by
σ = 1 / ρ ----------------------------- (3)
Mobility of charge carriers (µ) = σ * RH m2/vs. --------------------------(4)
Knowing the conductivity of the semiconducting material, the mobility of charge carriers in the material
can be obtained from the following relation.
1.5 DESCRIPTION EXPERIMENT SETUP:
The apparatus consists of a constant current source and digital panel meter. The current flowing through the
semiconductor and voltage developed can be read with the help of current meter and volt meter. The semi
conductor is taken in the form of a wafer and mounted on a strip. Four contacts were soldered on the wafer.
An electro magnet supplies uniform magnetic field. The magnetic field can be directly read from the panel
meter located on the power supply unit .The strength of the magnetic field can be varied with the help of a
potentiometer.
The circuit diagram for the measurement of Hall voltage is shown in figure 2.
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1.6 PROCEDURE:
1) The semiconductor is mounted on the probe strip and four electrical contacts re provided on the strip. The
circuit is connected as shown in figure 2. The lengthwise contacts are connected to current meter and
breadth wise contacts are connected to voltmeter.
2) The probe is placed in the gap of the electromagnets which provides magnetic field in direction
perpendicular to the current direction and adjusts the magnetic field to suitable value and keep constant.
3) The current through the semiconductor is adjusted to suitable value with te help of constant current source
and corresponding voltage polarity can be noted.
4) For different current values, the corresponding Hall voltage developed can be noted down with the help
of voltmeter and the results tabulated in table 1.
5) Now keep the current value constant at a constant value and the magnetic field is varied in steps of 500
gauss, at each set of magnetic field note down the corresponding Hall voltage. The observations are
tabulated in table 2.
6) Using the above observations plot the graphs. In one graph plot the current versus voltage at a constant
magnetic field. In second graph magnetic field versus Hall voltage. In both the cases the graphs will be
straight lines.
TABLE: 1:
At constant magnetic field ( B) = 2.5 gauss
S.NO CURRENT (I) mA HALL VOLTAGE (VH) mV
1
2
3
4
5
TABLE: 2:
At constant current (i) = 2.5 amp
S.NO MAGNETIC FIELD (B) gauss HALL VOLTAGE (VH) mV
1
2
3
4
5
1.7 Model graphs:
(1) Variation of Hall voltage with current (2) Variation of Hall voltage with magnetic field
Voltage(mv) Voltage(mv)
Current(mA) Magnetic field (B)
30 | P a g e
1.8 PRECAUTIONS:
1) Care should be taken to limit the current through the probe to a value less than that of its capacity
2) The probe should be properly centered and mounted in the magnetic field so that maximum voltage is
generated.
3) The potentiometer control of electro magnet is kept at a minimum value while switching on or off of the
power supply.
4) The potentiometer control of the current flow through the probe is also brought to zero while switching on
or off the current source.
5) Magnetic field should be varied gradually and slowly to avoid damage to the electromagnetic cols.
1.9 RESULT:
1) The Hall voltage measured (RH) = ---------------------m3/c
2) The mobility of charge carriers ( µ ) = ---------------------m2/vs
3) The Majority carrier concentration ( n or ρ )= -------------------/m3 .
VIVA-VOCE QUESTIONS
1) What is the application of the Hall Effect?
2) Why did Hall utilize the thin gold foil to do the experiment? However, the sample we utilize in this
experiment isn't necessarily thin?
3) Based on your experimental result, what is difference between n-type & p-type germanium Halleffect
wafers? 4) What do the red and black inks onthe samples represent? n-type or p-type germanium Hall Effect
wafers? Explain how you can make the conclusion.
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Expt. No: Date:
EXPERIMENT – 8
TO DETERMINE THE HYSTERESIS LOSS IN THE TRANSFORMER CORE USING
B-H CURVE UNIT.
1.1 AIM:
To determine the hysteresis loss in the transformer core using B-H curve unit.
1.2 APPRATUS:
S. No Equipment Range Type Quantity
1 B-H-Curve unit - Standard 1
2 CRO - Standard 1
3 Patch cards
- Standard 1
1.3 FORMULA :
Energy loss = 𝑁1
𝑁2 ×
𝑅2
𝑅1×
𝐶2
𝐴1 × SV × SH × Area of the loop (Joules / cycle ) / unit volume .
Where N1=number of turns in the primary coil= 200 turns.
N2=Number of turns in the secondary coil=100 turns.
Circumference of the coil = 2𝜋𝑟 =30 cm [since 1 m = 100 cm ]
𝑟 = 30 / 2𝜋 = 15/ 𝜋 [1cm = 1/100 m = 1/102 m ]
𝑟2 = (15/ 𝜋 )2 = 225 / 𝜋2 [1cm = 10 mm]
A1= 𝜋𝑟2 = 𝜋 (225 / 𝜋2
) = 225/(22/7) =225 /3.14 = 71.656 Cm2
= 71.656 χ10-4 m2
A 1= Area of cross section of core = 71.656 χ10-4 m2 .
L= length of the core
SV= Vertical sensitivity of the CRO
SH= Horizontal sensitivity of the CRO
C2 = 4.7 χ10-6 F .
R1= 0.1 Ω
R2 = 680 Ω
1.4 DESCRIPTION:
The experimental arrangement is shown in Figure. One of the specimen used in the unit is made using
transformer stampings. There are two windings on the specimen (primary and secondary). The primary is
fed to low A.C voltage (50 Hz). This produces a magnetic field H in the specimen. The voltage across R1
(resistance connected in series with primary) is proportional to the magnetic field. It is given to the input of
the CRO. The A.C. magnetic field induces a voltage in the secondary coil. The voltage induced is
proportional to dB/dt.
This voltage is applied to passive integrating circuit. The output of the integrator is proportional to B and fed
to the vertical input of the CRO. As a result of the application of voltage proportional to H the horizontal
axis and a voltage proportional to B is the vertical axis, the loop is formed as shown in figure.
32 | P a g e
1.5 PROCEDURE :
The unit one to force te B-H loop of the ferromagnetic specimen using a CRO is shown in Fig. A
measurement of area of the loop leads to the evaluation of energy loss in the specimen. The top view of the
unit is shown in figure. There are 12 terminals on the panel, sin patch cards are supplied with kit.
The value of R1 can be selected connecting terminal D to B or C.
(A-D=50 ohm; B-D=150 ohm; C-D=50 ohm)
A is connected to D. The primary terminals of the specimen is connected to ‘p’, ‘p’ secondary to ‘s’, ‘s’
terminals. The CRO is clibrated as per the instructions given in the manual of CRO. CRO is adjusted to
work on external mode (the time base is switched off). The horizontal and vertical position controls are
adjusted such that the spot is at the centre of the CRO screen.
The terminal marked GND is connected to the ground of the CRO. The ‘H’ is connected to the Horizontal
input of the CRO. The power supply of the unit is switched on. The hysteresis loop is formal. The horizontal
and vertical gains are adjusted such that the loop occupies maximum area on the screen of the CRO. Once
this adjustment is made, the gain controls should not be disturbed. The loop is traced on a translucent graph
paper. The area of the loop is estimated.
The connections from CRO is removed without disturbing the horizontal and vertical gain controls. The
vertical sensitivity of the CRO is determined by applying a known A.C voltage say 1 volt (peak to pak).
If the spot deflects by X cms for 1 volt, the vertical sensitivity is 1/x × 10-2 (volt/m). Let it be dV. The
horizontal sensibility of CRO is determined by applying a known A.C. voltage say 1 volt (peak to peak). Let
the horizontal sensitivity be SH (volt/m)
The transformer core may be replaced by ferrite ring and hysteresis loss in ferrite core can be found.
TABLE :
S.NO CH1
V/S
CH2
V/S
SV
cm
SH
cm
Area of
loop(mm)
Energy
loss(J/c/m3)
1.
2.
3.
4.
1.6 RESULTS:
Energy loss =……………………….Jouls cycle-1 m-3.
VIVA-VOCE QUESTIONS
1. What is susceptibility?
2. What is magnetization and how it can be achieve?
3. Does an atom with one electron in outer shell can behave like a bar magnet? or simply does an atom can
be equivalent to the bar magnet?
4. What is atomic dipole?
33 | P a g e
5. How to find the atomic dipole element?
6. What is magnetic field induction and magnetic field intensity, how you will define it and what is the
relationship between them?
7. How do you see magnetic field density in a region of magnetic field by bar magnet?
8. What is the unit of magnetic field induction (density) and magnetic field intensity and from which letters
we represent to them?
9. What is the role of external magnetic field in magnetization of the material, how atomic dipole moments
of atoms plays the role in the magnetization?
10. Can you explain the types of magnetic material (Diamagnetic, Paramagnetic, Ferromagnetic,
Antiferromagnetic) on the basis of atomic dipole moments?
11. In which unit you measure the magnetic field intensity H, meniscus height h in your observation?
12. Does you have plot the graph between h and H^2, if yes where you will use the slope of this graph and
why?
13. In which unit system you calculated the value of susceptibility, SI or CGS?
14. What is g in the susceptibility formula and unit of it?
15. What is Gauss Probe and for what purpose we use it?
16. What is an electromagnet, how do we use it to magnetize the material?
17. Why the FeCl3 liquid in Quinke’s tube rise or fall in the presence of external magnetic field?
18. Does magnetic field intensity will increase after increasing the current of an electromagnet?
19. What signifies value of the susceptibility in your experiment?
34 | P a g e
Expt. No: Date:
EXPERIMENT – 9
TO DETERMINE THE DISPERSIVE POWER OF A MATERIAL OF PRISM USING SPECTROMETER
11.
1.1 AIM: To determine the dispersive power of a material of prism using Spectrometer.
1.2 APPRATUS:
S. No Equipment Range Type Quantity
1 Spectrometer - Standard 1
2 Mercury vapor lamp 60 watts Standard 1
3 flint glass prism - Standard 1
4 reading lens - Standard 1
1.3 FORMULA:
PRINCIPLE: Refractive Index (µ): It is defined as
µ = velocity of light in vaccum
velocity of light in air
And
sinsin 2
sinsin
2
mA D
i
Ar
Where A Angle of Prism
Dm Angle of minimum deviation
the dispersive power of the material of the prism is given by 1
b g
av
w
Where
2
b g
av
Where b = the refractive index of the blue rays
g= the refractive index of the green rays.
1.4 PRELIMINARY ADJUSTMENTS:
The essential parts of spectrometer are
a) The telescope
b) The collimator
c) The prism table
The following adjustments are to be made before the commencement of an experiment with a
spectrometer.
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a) Eyepiece adjustment: the telescope is turned towards a bright object, say a white wall about 2 to 3
meter distance way and eyepiece is adjusted so that the cross wires are very clearly seen.
OBSERVATIONS:
Least count of the spectrometer (L.C) = 1 𝑚.𝑠.𝑑
𝑁𝑜.𝑜𝑓 𝑣.𝑠.𝑑 = 301/ 30 = 11 .
Angle of prism (A) = 600
b) Telescope adjustment: Focus the telescope towards a distant (infinity) object. Focusing is done by
changing the separation between the objective and the eyepiece of the telescope. Test for the absence of
parallax between the image of the distant object and vertical cross wire. Parallax effect exists, if the cross
wire and distant object are not at the same distance from your eyes. Now the telescope is adjusted for
receiving parallel rays. Henceforth do not disturb the telescope focusing adjustment.
c) Collimator adjustment: The slit of the collimator is illuminated with white light. The telescope is
turned to view the image of slit and the collimator screw is adjusted such that clear image of the slit is
obtained without parallax in the plane of the cross wires. The slit of the collimator is adjusted to be vertical
and narrow.
1.5 PROCEDURE:
a) Adjusting the prism to minimum deviation position:
1) The prism is placed on the prism table with the ground surface of the prism on to left or right
of the collimator. The ground face of the prism does not face either collimator or telescope.
2) The ray of light passing through the collimator strikes the polished surface of the prism and
undergoes deviation and emerges out through opposite polished surface as shown in figure.
The deviated ray is seen through the telescope in position T2.
3) Looking at the spectrum the spectrum, the table is now rotated to one side, so that the
spectrum moves towards undeviated path of the beam. The deviated ray also moves towards
same side for some time and then starts turning back even if the prism table is moved in the
same direction. The point at which the ray starts turning back is called the minimum deviation
position.
b) Finding angle of minimum deviation:
1) In the limiting position of spectrum, the deviation of the beam is minimum the telescope is
fixed on the blue color and the tangent screw is slowly operated until the point of intersection
of cross wire is exactly on the image. The readings for the blue color is noted in vernier-I and
vernier-II and tabulated in tabular form.
2) The telescope is now moved on to the red color, without disturbing the prism and again
readings on vernier-1 and vernier-II are noted and tabulated in table
3) Now the telescope is released and the prism is removed from the prism table. The telescope is
now focused on to the direct ray and readings in vernier-I and vernier-II are noted and
tabulated.
36 | P a g e
4) The difference of the readings between the deviated reading for blue color and the direct
reading gives the angle of minimum deviation for blue color (DB). Similarly the difference of
the readings between the deviated reading for red color and direct reading gives angle of
minimum deviation for red color (Dr).
5) The refractive indices for blue and red rays are calculated using equations (II) and (III),
(assuming angle of prism, A= 600). The values of µB and µR are substituted in equation (I) and
the dispersive power of material of the prism is calculated.
Fig 1: spectrometer
37 | P a g e
1.6 OBSERVATIONS:
Direct Reading:
Left (VL) = …………… Right (VR) =…………..
S.no Colours
Readings in minimum deviation position Angle of minimum
deviation (Dm) Refractive
Index ( µ ) Left Right
V1~VL V2~VR
Aver
age
(Dm) MSR VSC
TR
(V1) MSR VSC
TR
(V2)
1.7 PRECAUTIONS:
1. The telescope and collimator should be individually set for parallel rays.
2. Slit should be as narrow as possible.
3. While taking observations, the telescope and prism table should be clamped with the help of
Clamping screws.
4. Both vernier should be read.
5. The prism should be properly placed on the prism table for the measurement of angle of the Prism as well
as for the angle of minimum deviation
1.8 RESULT : Dispersive power of material of the given prism (ω) = ----------------
1.9 VIVA-VOCE QUESTIONS
1. What is spectrometer?
2. Define refractive index.
3. Define dispersive power of a prism.
4. How does refractive index change with wave length?
5. Does the deviation depend on the angle of prism?
6. What is prism?
7. Which colour in the spectrum is having maximum and minimum refractive index?
8. What is Refractive index?
9 . What is the function of Collimator?
10. What do you mean by Angle of Prism?
11. What is Dispersion of Light?
12. What is the main optical action of the prism?
13. What type of material prism is used in this experiment?
38 | P a g e
Expt. No: Date:
EXPERIMENT – 10
TO DETERMINE THE MAGNETIC INDUCTION AT VARIOUS POINTS ON THE
AXIS OF A CURRENT CARRYING CIRCULAR COIL, USING STEWART AND GEE’S
TYPE OF GALVANOMETER. 1.1 AIM:
To determine the magnetic induction at various points on the axis of a current carrying circular coil, using
Stewart and Gee’s type of galvanometer.
1.2 APPARATUS:
S. No Equipment Range Type Quantity
1 Stewart and gee’s galvanometer - Standard 1
2 DC power supply 60 watts Standard 1
3 ammeter plug key - Standard 1
4 commutator - Standard 1
5 rheostart and connecting wires.
Stewart and gee’s galvanometer, DC power supply, ammeter plug key, commutator, rheostat and connecting
wires.
1.3THEORY:
Imagine a circular coil of radius (a) meter, carrying (i) ampere current. Let (n) be the number of turns in the
coil. Then the magnetic induction at a point(x) meter away from the coil, is given by
B=𝝁𝟎𝒏𝒊𝒂𝟐
𝟐(𝒙𝟐+𝒂𝟐)𝟑𝟐
Also we have tangent law in magnetism. Let BH and B be the earth’s and applied magnetic fields which are
perpendicular to each other. A freely suspended needle in these fields comes to rest in a direction shown in
figure. If the needle makes an angle (θ) with direction of BH, then
Tan θ = 𝐵
𝐵𝐻
B = BH tan θ
1.4 PROCEDURE:
1) Stewart and Gees apparatus is so oriented that the circular coil is in magnetic meridian of the
magnetic needle. That means keeping the magnetometer platform exactly at ‘O’ of the scale, orient
the Stewart and Gee’s apparatus in such away that the magnetic needle is exactly below the circular
coil and parallel to it.
2) Set the aluminum pointer to 0 – 0 position.
3) Now connect the circuit as shown in figure.
4) Set the voltage to 6 or 8 V Dc so that the deflection at the centre position in the magnetometer does
not cross 60 – 60 .
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5) Initially if the keys were inserted in the gaps (1) and (2), then change them to the gaps (3) and (4).
Now the direction of current is changed, obviously deflection also get changed. However the
magnitude of deflection should be same. If deflection is different, then the coil is not exactly in the
magnetic meridian. So turn off the circuit and readjust the orientation.
6 Keeping the keys in the gaps (1) and (2) note the deflections (θ1) and (θ2) of the magnetic needle.
Then inserting the keys in the gaps (3) and (4) note down (θ3) and (θ4).
7 Now move the platform to the 2 cm away from the centre either towards east or towards west. Repeat
step (6).
8 Keeping the keys in the gaps (1) and (2) note the deflections (θ1) and (θ2) of the magnetic needle.
Then inserting the keys in the gaps (3) and (4) note down (θ3) and (θ4).
9 Now move the platform to the 2 cm away from the centre either towards east or towards west. Repeat
step (6).
10 Increasing the distance of platform from the coil, in steps of 2 cm, repeat step (6), till the deflection is
30.
11 Initially if the platform is moved towards east, then brought it back and move towards west. Repeat
the experiment in same manner. Deflections are entered in to the tabular form.
1.5 MODEL GRAPH:
Plot the graph, as shown in figure. (A) and (B) are called inflection points. The magnetic field of induction is
maximum at the centre and decreases quite rapidly as we move away from the centre. It reaches a constant
value at the points (A) and (B). The distance between (A) and (B) is found to be equal to the radius of the
coil (a).
TABLE:
S
.no
. Distance
between the
deflection
magnetomete
r and center
of coil.
(x) m
Deflection in the magnetometer when moved towards
Ta
n θ
B=BHtan
θ
B=𝝁𝟎𝒏𝒊𝒂𝟐
𝟐(𝒙𝟐+𝒂𝟐)𝟑
𝟐
East
West
Θ
1
Θ2
Θ3
Θ4
Mea
n
ΘE
tan
θE
Θ1
Θ2
Θ3
Θ4
Mea
n
Θw
Ta
n θ
W
𝜽
𝑬+
𝜽𝑾
𝟐
40 | P a g e
1.6 PRECAUTIONS:
1) Once the coil is set in the magnetic meridian of the magnetic needle it should not be disturbed.
2) Rheostat and ammeter should be kept at a distance from Stewart and Gee’s apparatus, otherwise
they would influence the magnetic needle.
3) The deflections must be in between 60 and 30.
4) While shifting the flat form towards east or west, the Stewart and Gee’s apparatus should be
firmly held, so that the coil does not get disturbed from the magnetic meridian of the needle
1.7 RESULT:
Magnetic induction at several points on the axis of current carrying circular coil is determined by using
Stewart and Gee’s type tangent galvanometer.
1.9 VIVA-VOCE QUESTIONS
1) What is the magnetic induction formula at a point x, away from the center of the circular coil?
2) What will be the Magnetic field value at the center of a current carrying coil?
3) Does earth’s horizontal magnetic field value remain same everywhere or it fluctuates?
4)What are the two factors to calculate the earth’s horizontal magnetic field value online.
5) The angle which you measure by the Deflection Magnetometer is with reference to the earth’s magnetic
field component or the magnetic field produced by current carrying coil?
6) Why do you put apparatus (Wooden Frame along with circular coil) in East-West Direction?
7) What is commutator and what its role in experiment?
8) What is he difference between Helmholtz coil and Solenoidal?
9) What is the relation between Gauss and Tesla?
10)What is the unit of magnetic field intensity H?
11)When you plot the graph in between the tan theta and distance, you observe Gaussian type shape of the
curve. On this curve you find the points of inflection what is the formula for that?
12)The magnetic field of induction increases one side of the center and decreases on other sides. Can we
create the uniform magnetic field with the help of this concept?
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