An alternating e.m.f. is applied to a pure capacitive circuit. The phase relation between e.m.f. and current flowing in the circuit is
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The mutual inductance of an induction coil is 5 H. In the primary coil, current reduces from 5 A to zero in 10-3 s. What is the e.m.f. induced in secondary coil ?
If the equation for the displacement of a particle moving on a circular path is given by (θ) = 2t3 + 0.5, where θ is in radians and t in seconds, then the angular velocity of the particle after 2 sec from its start is
A ball of mass m moving with a velocity V → collides head on elastically with another of the same mass m, but moving with a velocity V → in the opposite direction. After the collision
The power of an electric bulb marked as 40 W and 200 V used in a circuit of supply voltage 100 V will be
The expected energy of the electrons at the absolute zero is called
A metallic ring of radius 'r' and cross sectional area A is fitted into a wooden circular disc of radius R (R > r) . If the Young's modulus of the material of the ring is Y, the force with which the metal expands is
Consider the following statements regarding the magnitude of barrier potential of a PN junction:
1. It is independent of temperature
2. It depends on difference between fermi levels on two sides of junction.
3. It depends on forbidden energy gap on two types of semiconductors
4. It depends on impurity concentration in P and N type semiconductors
Which of the statements given above is/are correct?
Two spherical conductors A and B having equal radii and carrying equal charges on them, repel each other with a force F, when kept apart at some distance. A third spherical conductor C having same radius as that of A, but uncharged, is brought in contact with A, then brought in contact with B and finally removed away from both. The new force of repulsion between the conductors A and B is
The coefficient of friction between a body and the surface of an inclined plane at 450 is 0.5. If g=9.8 m/s2, the acceleration of the body downwards in m/s2 is
The gravitational force between two similar bodies at a given distance is F. If mass of one body is doubled and that of the other is halved, and distance between them is also doubled, then resulting gravitational force between them will become
The initial temperature of a body is 80oC. If its temperature falls to 64oC in 5 minutes and in 10 minutes to 52oC then the temperature of surrounding will be
Diwali rocket is ejecting 50g of gases/s at a velocity of 400 m/s. The accelerating force on the rocket will be:
At a certain place, the horizontal component of the earth's magnetic field is B₀, and the angle of dip is 60o. The intensity of earth's magnetic field at that place will be
Under a pressure head, the rate of volume of liquid through a capacillary tube is Q. If length of the capillary tube is doubled and diameter of the bore is halved, the rate of flow would become
A body travels for 15 sec starting from rest with constant acceleration. If it travels distances S₁,S₂ and S₃ in the first five seconds, second five seconds and next five seconds respectively the relation between S₁,S₂ and S₃ is
A body, whose momentum is constant, must have constant
A solid sphere rolls down two different inclined planes of same height, but of different inclinations. In both cases
A particle is viberating in a simple harmonic motion with an amplitude of 4 cm. At what displacement from the equilibrium position, is its energy half potential and kinetic ?
If at a height of 40 cm, the direction of motion of a projectile makes an angle π/4 with the horizontal, then its initial velocity and angle of projection are. respectively
If the distance between a point source and screen is made one third, then intensity of light (I) and the initial intensity of light will be related as :
There is a horizontal film of soap solution. On it, a thread is placed in the form of a loop. The film is pierced inside the loop and the thread becomes a circular loop of radius R. If the surface tension of the loop be T, what will be the tension in the thread?
A wheel is rotating at 900 r.p.m. about its axis. When the power is cut-off, it comes to rest in 1 minute. The angular retardation in radian/s2 is
The rise of liquid due to surface tension in a narrow capillary tube of diameter 'd' is 'h'. If the diameter is reduced to d/2 , the rise will be
Consider the following statements
Assertion (A) : In adiabatic compression, the internal energy and temperature of the system get decreased
Reason (R) : The adiabatic compression is a slow process
Of these statements
The variation of density of a solid with temperature is given by the formula