WBJEE Physics Test - 13

In which case there is maximum extension in the wire, if same force is applied on each wire

The induced e.m.f. produced in the primary and secondary coils is 2 mV and 5 mV respectively. If the rate of change of current is 20 A-s^-1, then coefficient of mutual induction of the secondary coil is

The distance between the plates of a condenser is reduced to 1/4 th and the space between the plates is filled up by a medium of dielectric constant (K) 2.8. The capacity is increases by

A cyclotron is accelerating proton, where the applied magnetic field is 2 T, the potential gap is 100 KV, then how much turn the proton has to move between the dees to acquire a kinetic energy 20 Me V

At the magnetic poles of the earth, a compass needle will be

A block of mass M is pulled along a horizontal frictionless surface by a rope of mass m. If a force P is applied at the free end of the rope, then force exerted by the rope on the block is

A space ship is launched into a circular orbit of radius R close to surface of earth. The additional velocity to be imparted to the space ship in the orbit to overcome the earth's gravitational pull is [g - acceleration due to gravity]

A long straight conductor carries an electric current of 2A. The magnetic induction at a perpendicular distance of 5m from the wire is (μ₀ = 4π x10^-7 Hm^-1)

Observers on tenth, fifth and ground floor of a tall building measure the velocity of a certain rain drop by an accurate method. The velocity of rain drop measured by three observers is found to be the same. This is because the gravitational force

A charged particle of mass 5 x 10^-6 Kg is held stationary in space by placing it in an electric field of strength 10⁶ N C^-1 directed vertically downwards. The charge on the particle is g = 10 ms^-2

The relation between time 't' and distance 'x' is: t = ax² + bx; where a and b are constants. The acceleration is

For a projectile, the ratio of maximum height reached to the square of flight time is (g = 10 ms^-2)

Two bodies of mass 10 kg and 5 kg moving in concentric orbits of radii R and r such that their periods are the same. Then the ratio between their centripetal acceleration is

The equation of a simple harmonic motion is x=0.34 cos (3000 t+0.74) where and t are in mm and s respectively. The frequency of the motion is

Substances which have identical chemical properties but differ in atomic weight are called

The bob of a simple pendulum is a spherical hollow ball filled with water. A plugged hole near the bottom of the oscillating bob gets suddenly unplugged. During the observation, till water is coming out, the time period of oscillation would

A wheel having moment of inertia 2 kg-m² about its vertical axis, rotates at the rate of 60 rev-min^-1 about this axis. The torque, which can stop the wheel's rotation in one minute, would be

The moment of inertia of a uniform circular disc of radius 'R' and mass 'M' about an axis passing from the edge of the disc and normal to the disc is

To a germanium sample, traces of gallium are added as an impurity. The resultant sample would behaves like

When the conductivity of a semiconductor is only due to breaking of covalent bonds, the semiconductor is called

If m is the mass, θ is temp. and 's' is specific heat, then thermal capacity k is given by

An air bubble is contained inside water. It behaves as a

First law of thermodynamics is a special case of

Which of the following pair does not have similar dimensions

A vector b=3i+4k, is equal to the sum of vectors B₁ and B₂ where B₁ is parallel to A=i+j and vector B₂ is perpendicular to A. Then B₁=

The superposition principle applies to

On stretching a spring by 0.1 m, a elastic potential energy of 5 J is stored in it. The force constant of the spring is

The position-time graph of an object moving in a straight line is shown below. The object has zero velocity at

Two circular loops X and Y are placed parallel to each other coaxially .A clockwise current is flowing in X as seen from Y .The loops will repel each other if the current in X is

Assume that the density of air in the atmosphere does not change with altitude. If the height of atmosphere extends upto approximately 8km, what is the density of air at sea level?

A planet in a distant solar system is 10 times more massive than the earth and its radius is 10 times smaller . Given that the escape velocity from the earth is 11 kms^-1, the escape velocity from the surface of the planet would be

The length of a simple pendulum is about 100 cm known to an accuracy of 1 mm. It's period of oscillations using a clock of 0.1 s resolution. What is the accuracy in the determined value of g?

A proton moving with a constant velocity passes through a region of space without any change in its velocity. If E and B represent the electric and magnetic fields respectively, this region of space may have

A strip of wood of mass M and lenght ℓ is placed on a smooth horizontal surface, an insect of mass m starts at one end of the strip and walks to the other end in time t moving with constant speed.

A particle of charge +q and mass m moving under the influence of a uniform electric field Eî and uniform magnetic field B k^{^} follows a trajectory from P to Q as shown in fig. The velocities at P and Q are vî  and -2 v j^ which of the following statement(s) is/are correct ?

Three simple harmonic motions in the same direction each of amplitude 'a' and periodic time 'T' are superposed. The first and second, and the second and third differ in phase from each other by π/4 , with the first and third not being identical. Then

A given quantiy of an ideal gas is at pressure P and absolute temperature T. The isothermal bulk modulus of the gas is