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

Two thin lenses of focal lengths 20 cm and 25 cm are placed in contact. The effective
power of the combination is

Light of wavelength $\\lambda$ and photon energy 2 eV falling on a metal surface produces
photoelectrons of maximum velocity v. If $\\lambda$ is decreased by 25% and the maximum velocity is doubled,
the work function of metal (in eV) is

The de-Broglie wavelength associated with proton changes by 0.25% if its momentum is
changed by $p_0$. The initial momentum was

A closed cubical box is completely filled with water and is accelerated horizontally towards
right with constant acceleration a. The resultant normal force by the water on the top of the box