physics 9th mcqs

8/11/2019 Physics 9th Mcqs

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M.IMRAN KHAN 0321-8875743 TANVEER RASHEED KHAN 0331-4313402 Page 1

Ch#1 PHYSICAL QUANTITIES AND MEASUREMENTS

Multiple Choice Questions

The branch of science which deals with the study of matter, energy and

their mutual relationship is called:

Physics Geology Chemistry

The study of matter at very high temperature:

Astrophysics Plasma Physics sound

The study of internal structure of earth and its activities is called:

Solid state physics Geophysics Mechanics

The study of isolated nuclei of an atom is called:

Plasma Physics Astrophysics Nuclear Physics

Much of the universe is made up of:

Plasma Solid Liquid

The International System of Units is abbreviated as:

IS SI None

The term used internationally for multiples and submultiples is:

Prefixes Scientific Notation Standard

Meter Rule can measure the length up to:

1mm 1cm 1m

The instrument which can measure up to one tenth of millimeter:

Vernier Calipers Screw Gauge None

The SI unit of intensity of heat is:

Newton Candela Kelvin


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o

One meter is equal to:

103mm 102cm Both

o

Volume measuring scale has a vertical scale in:

Millimeter cm3 Both

o The least count of Vernier Caliper is:

0.01cm 0.1mm Both

o Total length of Vernier scale is:

9mm 10mm 1cm

o Number of divisions on the Vernier scale are:

1 10 100

o Length of the smallest division on the main scale of the Vernier calipers

is:

1cm 1mm None

o If the zero of the Vernier scale in on the right side of the main scale then

zero error is:

Positive Negative No error

o If the zero of the Vernier scale in on the left side of the main scale then

zero error is:

Positive Negative No error

o If the zero of the Vernier scale in on the right side of the main scale then

zero error is to be:

Added Subtracted Divided

o If the zero of the Vernier scale in on the left side of the main scale then

zero error is to be:

Added Subtracted Multiplied

o The least count of Screw Gauge is:


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0.1mm 0.01mm 0.1cm

Total number of divisions on the circular scale of Screw Gauge are:

10 20 100

Pitch of the Screw Gauge is:

1m 1mm 1cm

If the zero of the circular scale is above the horizontal line then zero error

will be:

Positive Negative No Error

If the zero of the circular scale is below the horizontal line then zero error

will be:

Positive Negative No Error

If the zero of the circular scale is above the horizontal line then zero error

is to be:


If the zero of the circular scale is below the horizontal line then zero error

is to be:


There should be --------- digit(s) before the decimal point:

One Two Three

In Screw Gauge, the distance moved forward or backward in one complete

rotation of the circular scale is known as:

Least Count Pitch Constant

A physical balance is used to measure:

Weight Length Mass

Least count of mechanical stop watch is:

1sec 1min. 0.1sec


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Least count of digital stop watch is:

0.01sec 0.1sec 1min.

In any measurement, the accurately known digits and first doubtful digit

are known as:

Prefixes Significant figures Real numbers

The radius of wire is 0.034cm. The number of Significant figures in the

measurement are:

2 3 4

The number of Significant figures in 1.507 are:

4 3 1

The number of significant figures in 1.45 x 105are:

3 2 1

Vernierconstant is also known as----------- of Vernier calipers:

Pitch Least Count Vernier Value

The zeros in between the digits are considered:

Insignificant Constant Significant

106stand for:

Micro Mega Pico

1s is equal to:

10-6s 103s 1012s

The number of base units in SI System are:

3 5 7

Which one of the following is a derived unit?

Pascal Kilogram Meter

Identify the base quantity in the following:


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Speed Pressure Distance

Short Questions:

What is Science?

The knowledge gained through observations and experiments is known as science.

Define Physics:

The branch of science which deals with the study of matter, energy and their mutual

relationship is known as Physics.

What are the physical quantities?

All measureable quantities are called physical quantities.

Example:

Length, time, mass, force, speed, volume etc.

What are basic characteristics of physical quantities?

A physical quantity at least has two characteristics:

1- Numerical magnitude

2- Unit in which it is measured

What are base quantities?

The physical quantities which form the foundation for other physical quantities are

called base quantities. These are seven in number.

Example:

These are length, time, mass, electric current, intensity of light, quantity of matter andtemperature.

What are derived quantities?

The quantities which can be described in terms of base quantities are known as

derived quantities.

Example:


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Force, area, volume, density etc.

What do you mean by International System of Units?

In the eleventh general conference on weight and measurements held in Paris in 1960

a worldwide system of measurements was adopted. This system is known as

International System of Units and abbreviated as SI.

What are base units?

The units that describe the base quantities are called base units. There are seven base

units.

Example:

Base quantities Base Units

Length Meter

Mass Kilogram

Time Second

Electric Current Ampere

Intensity of Light Candela

Temperature Kelvin

Quantity of Matter Mole

What are derived units?

The units used to measure derived quantities, which are derived from base quantities

are called derived units.

Example:

Unit of speed is meter per second m/sec

Unit of force is Newton (N)

Unit of volume is meter cube m3

What do you understand by the term prefixes?

The term used internationally for the multiples and submultiples for various units are

known as prefixes.

Example:

Multiples Prefixes


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10-9 Nano

10-3 Milli

106 Mega

1012 Tera

Define the branches of Physics:

There are different branches of physics which are given as under:

Mechanics:

It is the study of motion of objects, causes and effects.

Heat:

This branch of physics deals with the nature of heat, modes of transfer and its effects.

Sound:

This branch deals with the physical aspects of audible sound waves, their production,

properties and applications.

Light:

It is the branch of physics that deals with the physical aspects of light, its properties,

working and use of optical instruments.

Electricity and Magnetism:

It is the study of charges in rest and motion, their effects and their relationship with

magnetism.

Atomic Physics:

it is the study of the structure and properties of atoms.

Nuclear Physics:

This branch deals with the properties and behavior of nuclei and particles within the

nucleus.

Plasma Physics:

it is the study of production, properties of ionic state of matter, the forth state of the

matter.


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Geophysics:

It is the study of the internal structure of Earth.

What role SI units have played in the development of science?

With the developments in the field of science and technology, the need for the

commonly acceptable system of units was widely felt all over the world particularly to

exchange scientific and technical information.

What is Vernier constant?

The difference between one main scale division and one Vernier division is called

Vernier constant. This is the minimum length which can be measured with Vernier

caliper. It is also called the least count of Vernier calipers.

What do you understand by the zero error of a measuring instrument?

In Vernier caliper, if the zero of the main scale does not coincide with the zero of the

Vernier scale then it is called zero error.

Why is the use of zero error necessary in measuring instruments?

The use of zero error is necessary in measuring instruments to take correct

measurements.

What is meant by significant figures?

in any measurement, the accurately known digits and first doubtful digit is known as

significant figures.


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Solution to Problems:

1.1

Express the following quantities using prefixes;

Solution:

Ans:

a) 5000 g = 5 x 103g = 5kg

b) 2000000 W = 2 x 106W = 2MW

c) 52 x 10-10 kg = 5.2 x 101x 10-10x 103 = 5.2 x 10-6= 5.2 g

d) 225 x 10-8 s = 2.25 x 102x 10-8= 2.25 x 10-6= 2.25 s

1.2

How do the prefixes Micro, Nano and Pico relate each other?

Ans:

1 Pico = 1p = 10-12

1 Nano = 1n = 10-9

1 micro = 1 = 10-6

1 = 1000n

1n = 1000p

1.3 your hairs grow at the rate of 1mm per day. Find their growth rate in

mm/s:

Ans:

Rate of growth = 1mm/ day

As 1mm = 1000000nm

And 1 day = 24 x 60 x 60 s

= 1000000/24 x 60 x 60


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= 11.57 nm/sec

1.4 Rewrite in the standard form:

Ans:

a) 1168 x 1027= 1.168 x 103x 10-27 = 1.168 x 10-24

b) 32 x 105 = 3.2 x 101 x 105 = 3.2 x 106

c)

725 x 10-5 kg = 7.25 x 102 x 10-5 103 g = 7.25 g

d) 0.02 x 10-8= 2 x 10-8x 10-2 = 2 x 10-10

1.5 write the following quantities in standard form:

Ans:

a)6400km = 6.4 x 103 x 103 = 6.4 x 106 m

b)380000 km = 3.8 x 105x 103 = 3.8 x 108

c)300000000 ms-1= 3 x 108 ms-1

d)Seconds in a day = 24 x 60 x 60 = 86400 sec = 8.6 x 104 sec

1.6

On closing the jaws of a Vernier caliper, zero of the Vernier scale in on the

right of its main scale such that 4thdivision of its Vernier scale coincides

with one of the main scale division. Find its zero error and zero

correction.

Ans:

Number of divisions of main scale = 4

Least count of the Vernier caliper = 0.01 cm

Zero error = 4 x 0.01 = 0.04cm

As zero of the Vernier scale is at the right side of the zero of the main scale so zero

error will be positive.

So zero correction = -0.04cm

1.7 A screw gauge has 50 divisions on its circular scale. The pitch of the screw

gauge is 0.5mm. What is its least count?


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Ans;

As least count = pitch of the screw gauge / number of circular scale divisions

Least count = 0.5/50 = 0.01mm = 0.001cm

1.8 Which of the following quantities have three significant figures?

Ans: b and c

1.9 what are the significant figures in the following measurements:

Ans:

a) 4

b) 3

c) 3

d) 4

1.10 A chocolate wrapper is 6.7cm long and 5.4cm wide. Calculate its area up

to the reasonable number of significant figures.

Ans:

Given data:

Length = 6.7cm

Width = 5.4cm

Required:

Area = ?

Solution:

As we know that

Area = Length x Width

Area = 6.7 x 5.4

Area = 36.018 cm2


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Result:

As the least number of the significant figures in measurement are 2

So Area = 36cm2

Ch#2 KINEMATICS

Multiple Choice Questions

Study of motion of bodies is:

Mechanics Velocity Speed

Study of motion without the reference of force and motion is called:

Kinematics Dynamics Motion

If a body does not change its position with respect to an observer then its

state will be:

Motion Rest Relative

If a body changes its position with respect to an observer then its state

will be:

Motion Rest Relative

Rest and motion are states:

Constant Absolute Relative

Such a type of motion in which every particle of a body has the same

motion is called:

Translatory Vibratory Rotatory

When a body moves a fixed point or axis then motion of the body is known

as:


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When a body moves to and fro about a point or axis then its motion is

called;


Motion of dust and smoke particles in the air:

Circular Random Linear

Total length between two points is called:

Distance Displacement Speed

The shortest distance between two points is known as:

Position Velocity Displacement

SI unit of speed is:

m/sec m/hr km/sec

Speed is a . quantity:

Vector Scalar Both

The rate of change in displacement with respect to time is called:

Speed Velocity Acceleration

If the speed and direction of the moving body does not change with time

then its velocity is said to be:

Uniform Variable Constant

If the speed and direction of the moving body change with time then its

velocity is said to be:

Uniform Variable Constant

Rate of change of velocity is called:

Acceleration Speed Distance


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If the velocity of body is increasing then its acceleration will be:

Positive Negative None of these

If the velocity of body is decreasing then its acceleration will be:

Negative Retardation Both

If the velocity of the body is uniform then its acceleration will be:

Positive Negative Zero

SI unit of acceleration is:

m/sec kms-2 ms-2

If the velocity of the body changes equally in the equal intervals of time

then its acceleration will be:

Uniform Variable Relative

The quantity which can be described by a number and a suitable unit only

is called:

Vector Scalar Speed

The quantity which is described by its magnitude as well as direction is

called:

Vector Scalar Velocity

What is the value of g?

9.8 m/sec2 980cm/sec2 Both

Series of experiments on the free fall of heavy bodies were performed by:

Newton Galileo Einstein

If a body is falling under gravity then its initial velocity will be:


If a body is falling under gravity then its gravitational acceleration will be:


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If a body is thrown vertically upward then its final velocity will be:


If a body is thrown vertically upward then its gravitational acceleration

will be:


If a car is moving with uniform speed in a circle then its velocity will be:

Uniform Variable Same

There are equations ofmotion:

3 4 2

A train is moving at a speed of 36km/hr. Its speed expressed in m/sec is:

10m/sec 20m/sec 36m/sec

A body has Translatory motion if it moves along its:

Straight line Circle Both

A ball is thrown vertically upward. Its velocity at the highest point will be:

-10m/sec 10m/sec Zero

Short Questions:


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Define kinematics.

The study of motion of an object without discussing the cause of motion is called

kinematics.

Define Dynamics:

Dynamics is the branch of mechanics concerned with the forces that cause motion of

bodies.

How will you define the rest?

If a body does not change its position with respect to an observer then it is said to be

in rest position.

Example:

1. Trees along the roads

2. Furniture in a room

How will you define the motion?

If a body changes its position with respect to an observer then it is said to be in a state

of motion.

Example:

1. Vehicles on the road

2. Flying Birds

how can we say that rest and motion are relative states?

The state of rest or motion is relative. For example, a passenger sitting in a moving

bus is at rest with respect to other passengers. But to an observer outside the bus, the

passengers are in motion because they are changing their position.

Define Rotatory motion:

The spinning motion of a body around its axis is called Rotatory motion.

Example:

Motion of earth around its axis

Motion of ceiling fan

Define axis of rotation?


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A line around which a body rotates is called axis of rotation.

Differentiate between circular and Rotatory motion.

In circular motion, the point about which a body moves around, is outside the body,

while in rotatory motion, the line around which a body moves about is passing

through the body itself.

Define vibratory motion:

When a body moves to and fro about its main position is called vibratory motion.

Example:

Motion of see-saw

Motion of pendulum of wall clock

Differentiate between scalar and vector quantities:

Scalar:

A physical quantity which can be described by its magnitude and appropriate unit is

called scalar.

Example:

Mass, length, time, speed etc.

Vector:

A physical quantity which can be completely described by its magnitude along with its

direction is known is vector.

Example:

Velocity, force, torque, displacement etc.

What do you know about vector representation?

Symbolic Representation:

To represent vectors, we generally use bold letters to represent vector quantities.

Example:

F, a, d or a bar or arrow over their symbols.


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Graphical representation: B

Graphically, a vector is represented by a line with an arrow head.

The arrow head represents the vector and length of the line gives

The magnitude of the vector. A

What is position?

The term position defines the location of a place or an object with respect to some

reference point.

What is meant by distance?

Distance:

The total length of a path between two points is known as distance.

Quantity:

It is a scalar quantity.

Unit:

Its unit is meter (m).

Representation:

Distance is represented by S.

Formula:

Distance = speed x time

S = v x t

What do you know about displacement?

Displacement:


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The shortest distance between two points is known is called displacement which has

magnitude and direction.

Quantity:

Displacement is a vector quantity.

Unit:

Its unit is meter (m).

Representation:

It is represented by d.

Formula:

Displacement = velocity x time

d = v x t

Define speed:

Speed:

The distance covered by an object in unit time is known as its speed.

Quantity:

Speed is a vector quantity.

Unit:

Its unit is meter per second (m/sec).

Formula:

Speed = Distance / Time

V = s/t

How will you define the uniform speed?

If a body covers equal distances in equal intervals of time, however small the intervals

may be, the speed of the body is said to be uniform.

A body is moving with uniform speed. Will its velocity be uniform?


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If a body is moving with uniform speed may have uniform or variable velocity. If the

direction of the body is not changing then its velocity will be uniform.

Example 1:

A body moving with uniform speed in straight line will have uniform velocity.

Example 2:

A body moving with uniform speed in circle will have variable velocity because its

direction changes at every point.

What do you know about velocity?

Velocity:

The rate of displacement of a body with respect to time is known as displacement.

Quantity:

Velocity is a vector quantity.

Unit:

Its unit is meter per second (m/sec).

Formula:

Velocity = displacement / time

V = d/t

What is uniform velocity?

A body has uniform velocity if it covers equal displacement in equal intervals of time

however short the interval may be.

Example;

Motion of car with uniform speed in the straight line.

What do you mean by variable velocity?

If the speed or direction of the moving body changes with time then its velocity is said

to be variable.

Example:


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Body moving in circular path.

What is meant by acceleration?

Acceleration:

The rate of change of velocity of a body is known as acceleration.

Quantity:

Acceleration is a vector quantity.

Unit:

Its unit is m/sec2

Formula:

Acceleration = change in velocity / time

a = vf- vi/ t

What is meant by uniform acceleration?

If a body has equal changes in velocity in equal intervals of time, however small the

intervals may be, then the acceleration is said to be uniform.

What is meant by positive and negative acceleration?

Positive Acceleration:

If the velocity of the moving body is increasing then acceleration will be positive. In

positive acceleration direction of the body does not change.

Example:

If a car is moving is a straight line and driver press the accelerator the velocity of the

car starts to increase, so the acceleration of the body will be positive.

Negative acceleration / Retardation:

If the velocity of the moving body is decreasing then acceleration will be Negative. In

positive acceleration direction of the body is opposite to the direction in which the

body is moving. Negative acceleration is also called Retardation.

Example:


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If the driver applies brake, the velocity will start to decrease. So acceleration will be

negative and direction of acceleration is opposite to the direction of velocity.

A body moving with uniform velocity. What will be its acceleration?

A body is moving with uniform velocity then its acceleration will be zero because

acceleration is defined as the rate of change of velocity.

What do you know about graph?

Graph is a pictorial way of presenting the information about the relation between

various quantities. The quantities used in plotting a graph are called variables.

What do you mean by dependent and independent variables?

Independent Variable quantity:

The quantity which can be changed with our wish is called independent variable.

Dependent variable quantity:

the quantity, value of which varies with the change in independent variable quantity is

called dependent variable quantity.

What do you know about gravitational acceleration?

The acceleration of freely falling bodies is known as gravitational acceleration. It is

represented by g and its value is 9.8 m/sec2.

How can we use equations of motion for freely falling bodies under gravity?

Equations of motion can be used for freely falling bodies. In such cases we replace a

by g and S by h. so equations of motion for bodies freely falling can be written as:

a) Vf = Vi + at

b) h = Vit + at2

c) 2gh = Vf2Vi2

What are the points kept in mind when bodies are moving freely under gravity?

When bodies are moving in downward direction:

Initial velocity Vi of the freely falling body will be zero.

Gravitational acceleration will be positive.

When bodies are moving in upward direction:


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M IMRAN KHAN 0321-8875743 TANVEER RASHEED KHAN 0331-4313402 Page 23

Final velocity Vf of the freely falling body will be zero.

Gravitational acceleration will be negative.

When a body is thrown vertically upward, its velocity at the highest point is

zero. Why?

When a body moves upward, it moves under gravity against the force of attraction of

earth. So after every second the velocity decreases and ultimately becomes zero at the

highest point.

physics 9th mcqs

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