# WBJEE Physics Test - 1

## 40 Questions MCQ Test WBJEE Sample Papers, Section Wise & Full Mock Tests | WBJEE Physics Test - 1

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Attempt WBJEE Physics Test - 1 | 40 questions in 60 minutes | Mock test for JEE preparation | Free important questions MCQ to study WBJEE Sample Papers, Section Wise & Full Mock Tests for JEE Exam | Download free PDF with solutions
QUESTION: 1

Solution:

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QUESTION: 2

Solution:
QUESTION: 3

### An ammeter gives full deflection when a current of 2 amp. flows through it. The resistance of ammeter is 12 ohms. If the same ammeter is to be used for measuring a maximum current of 5 amp., then the ammeter must be connected with a resistance of

Solution:
QUESTION: 4

Two similar wires under the same load yield elongation of 0.1 mm and 0.05 mm respectively. If the area of cross-section of the first wire is 4 mm2, then the area of cross section of the second wire is

Solution:
QUESTION: 5

The mutual inductance of an induction coil is 5 H. In the primary coil, the current reduces from 5 A to zero in 10-3s. What is the induced emf in the secondary coil ?

Solution: QUESTION: 6

There is a uniform electric field of strength 103 V m−1 along Y-axis. A body of mass 1 gm and charge 10− 6C is projected into the field from orgin along the positive X-axis with a velocity of 10 m s − 1 . Its speed in m s−1 after 10s is (Neglect graviation )

Solution: QUESTION: 7

Which of the following quantities does not depend upon the orbital radius of the satellite

Solution:
QUESTION: 8

The centripetal acceleration of a body moving in a circle of radius 100 cm with a time period of 2s will be

Solution:

100cm=1m

a=v²/r

v= 2πr/t

v=6.28/2

v= 3.14

a= 9.8596/1

a=9.8596 m/s²

QUESTION: 9

A capacitor of capacity C1 is charged upto V volt and then connected to an unchanged capacitor of capacity C2. The potential difference across each capacitor will be

Solution:

Charge on first capacitor = q1 = C11
Charge on second capacitor = q2 = 0
When they are connected, in parallel the total charge
q = q1 + q2
∴ q = C11
and capacitance, C = C1 + C2
Let V' be the common potential difference across each capacitaor, then q = CV' QUESTION: 10

The coil of a moving coil galvanometer is wound over a metal frame in order to

Solution:
QUESTION: 11

If a bar magnet of moment μ is suspended in a uniform magnetic field B and it is given an angular deflection ' θ ' w.r.t its equilibrium position, the restoring torque on magnet is

Solution:
QUESTION: 12

The coil in the tangent galvanometer must be kept

Solution:
QUESTION: 13

Two mercury drops with radii in the ratio of 3 : 4 fall from a great height through the viscous liquid. The ratio of their terminal velocities is

Solution:
QUESTION: 14

The x and y coordinates of a particle at any time t are by x=7t+4t2 and y=5t, where x and y are in metre and t in seconds. The acceleration of particle at t=5 s is

Solution:
QUESTION: 15

A bullet is fired from a gun with a velocity of 1000 m−s-1 in order to hit a target 100 m away. At what height above the target should the gun be aimed? (Resistance of air is negligible and g = 10 m−s⁻2)

Solution:
QUESTION: 16

The centripetal acceleration is given by

Solution:
QUESTION: 17

Two radioactive substances A and B have decay constants 5 λ and λ respectively. At t = 0 they have the same number of nuclei. The ratio of number of nuclei of A to those of B will be after a time interval

Solution:
QUESTION: 18

The length of a simple pendulum is increased by 1%. Its time period will

Solution:
QUESTION: 19

One-fourth length of a spring of force constant K is cut away. The force constant of the remaining spring will be

Solution:
QUESTION: 20

A solid cylinder of mass M and radius R rolls on a flat surface. Its moment of inertia about the line of contact is

Solution:
QUESTION: 21

Which of the following spectrum has high to low frequency range?

Solution:
QUESTION: 22

A soild sphere, disc and solid cylinder all of the same mass and made of the same material are allowed to roll down (from rest) on an inclined plane, then

Solution:
QUESTION: 23

In forward biasing of junction diode, the width of depletion layer

Solution:
QUESTION: 24

In p-type semiconductor, majority current carriers are

Solution:

In a ptype semiconductor, the majority charge carriers are the holes whereas in the n- type semiconductor, the majority charge carriers are the free electrons.

QUESTION: 25

Heat given to a body which rises its temperature by 1ºC is

Solution:
QUESTION: 26

The length and breadth of a metal sheet are 3.124 m and 3.002 m respectively. The area of this sheet up to four correct significant figures is

Solution:
QUESTION: 27

The vector lies in the plane of vectors which of the following is correct ?

Solution:
QUESTION: 28

Doppler's effects in sound and light are

Solution:
QUESTION: 29

Two springs, having spring constants of 25 N-m⁻1 and 16 N-m⁻1are stretched by forces F₁ and F₂.If work done in stretching the springs is equal, then the ratio of the forces F₁ and F₂ is

Solution: QUESTION: 30

An unknown resistance X is connected in the left gap and a known resistance R in the right gap of a meter bridge. The balance point is obtained at 55 cm from the left end of the wire. When R is increased by 5 Ω , the balance point shifts by 5 cm. The value of X is

Solution:
QUESTION: 31

The maximum range of a projectile fired with some initial velocity of found to be 1000 metre, in the absence of wind and air resistance. The maximum height h reached by this projectile is

Solution:
QUESTION: 32

The speed of a train increases at a constant rate α from zero to v and then remains constant for an interval and finally decreases to zero, at a constant rate β . The total time taken to cover a total distance l is given by

Solution:
QUESTION: 33

A bob of mass M is suspended by a massless string of length L. The horizontal velocity V at position A is just sufficient to make it reach the point B. The angle θ at which the speed of the bob is half of that at A, satisfies Solution:
QUESTION: 34

Of two masses of 5 kg each falling from height of 10m, by which 2 kg water is stirred. The rise in temperature of water will be

Solution:
QUESTION: 35

Assuming the coefficient of friction between the road and tires of a car to be 0.5, the maximum speed with which the car can move around a curve of 40.0m radius without slipping if the road is unbanked, should be

Solution: *Multiple options can be correct
QUESTION: 36

A charged particle begins to move in a magnetic field, initially parallel to the field. The direction of the field now begins to change with its magnitude remaining constant. Choose incorrect statement(s) from the following.

Solution:
*Multiple options can be correct
QUESTION: 37

A particle is moving in a circle of radius R in such a way that at any instant the radial acceleration and tangential acceleration are equal. Speed at t = 0 is v0 and angular speed is ω0 . Then

Solution:
*Multiple options can be correct
QUESTION: 38

A small ball is connected to a block by a light string of length ℓ . Both are initially on the ground. There is sufficient friction on the ground to prevent the block from slipping. The ball is projected vertically up with a velocity u where 2gℓ < u2 < 3gℓ . The centre of mass of the "block + ball" system is C. Then Solution:
*Multiple options can be correct
QUESTION: 39

A thin uniform rod of mass M and ℓ is suspended vertically from fixed end A. A small ball of mass m moving with a velocity v0 collides normally at end B and gets stuck to it. Then

Solution:
QUESTION: 40

A point source of sound is emitting sound waves of frequency 1000 Hz. The source starts moving to the right with a speed of 32 m/s relative to ground while a reflecting surface which is on the righ side of source is approaching the source with a speed of 64 m/s relative to ground. The speed of sound in air is 332 m/s. For this situation, mark out the correct statement(s).

Solution:

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