A lens is placed between a source of light and a wall. It forms images of area A1 and A2 on
the wall, for its two different positions. The are of the source obtained is

A body is thrown horizontal from the top of a tower and strikes the ground after three seconds
at an angle of 45° with the horizontal. Then find the height of the tower

The gravitational field due to a mass distribution is I= $\\dfrac{C}{x^{2}}$ in x direction. Here, C is constant.
Taking the gravitational potential to be zero at infinity, potential at x is:

Figure shows a rectangular coil of cross-sectional area A placed in a uniform magnetic field B
directed along z-axis. The torque on coil is

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is -20°C,
the temperature of the surroundings to which it rejects heat is

In an LCR circuit, the potential difference between the terminals of the inductor is 60 V,
between the terminals of capacitor is 30 V and that between the terminals of resistor is 40 V.
The supply voltage is

Assertion : Microwave have more energy than the radiowaves.
Reason : Energy E = $hc/\\lambda$.
A. Both, Assertion and Reason are true and the Reason is correct explanation of the Assertion.
B. Both, Assertion and Reason are true but the Reason is not correct explanation of the Assertion.
C. Assertion is true but the Reason is false.
D. Both, Assertion and Reason are false.

If the number of steady revolutions per minute of a conical pendulum is increased from 75 to
80, the difference in the level of bob would be

If both the mass and radius of the earth decreases by 1%, then

A Carnot engine, having an efficiency of $\\eta = $\\dfrac{1}{10}$ as heat engine, is used as a refrigerator. If
the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is