Revise all concepts, definitions, laws,
formulae and units
Tables of 1 to 30 squares and square
roots of 1 to 30 cubes of 1 to 10
Questions of Deep Knowledge
1 Which of the following quantities have unit, but not the dimensions.
(a) dielectric constant
(b) coefficient of viscosity
(c) plane angle
(d) refractive index
2. A block of mass 10kg is resting on a horizontal surface. A force of 50N is applied on it. If coefficient of friction between the block and the surface is 0.6. what will be the force of friction? (g = 10 m/s2)
(a) Zero
(b) 50 N
(c) 60 N
(d) 40 N
CORRECT OPTION IS
(b) 50 N
fs = mgμ
fs = 10×10×0.6
fs = 60N
But applied force is 50N.
Hence, the block will not move.
Questions of Presence of mind
1. Three tuning forks of frequencies 400 H2, 401 Hz and 402 Hz are
sounded together. How many beats will be heard?
(a) 3
(b) 5
(c) 6
(d)1
2. Three tuning forks of frequencies 400Hz, 401Hz and 402H2 are
sounded together. How many beats will be produced?
(a) 3
(b) 5
(c) 6
(d)1
Solution:
g
Rcos
R cos
g
R cos2
g
1 g
2 R cos
3. A hemispherical bowl of radius R is revolved around its vertical axis. A Light weight sphere in it also revolves in it, without sliping. The radius of the hemispherical passing through the sphere makes angle θ with the axis of rotation. The angular velocity of the sphere is:
(a) (b)
(c) (d)
Solution:Motion of the sphere is like motion of conical pendulum.Hence R cos
T 2g
2but T
2 R cos2
g
g
R cos
Questions on application mind
1.Charge q moves around charge Q in circular path. The work done by charge Q on q is
(a) (b)
(c) Zero (d)
20
1 Qq
4 k r 0
1 q
4 k r
20
1 Qq2 r
4 k r
Solution: Charge q is moving over an equipotential surface Hence, work done is zero.
2. Time taken by radio waves to go come back from communication satellite is nearly
(a) 1s (b)
(c) (d) 4s
1s
4
1s
8
Height of communication satellite above the surface of the earth is 36000 km.
∴ Distance travelled by radio waves = 72000 km
Velocity of radio waves = 3 × 108 m/s
8
6
6
72000kmtime
3 10 m / s
72 10 1time
300 10 4
Full Portion Tests
Time Table
Time Allotment
Mistakes
Confidence
Thank
you ...!