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

Assertion : The nature of X-ray spectrum is continuous.
Reason : X-rays arise due to jumps of electrons from higher orbit to one of the inner orbit in an atom.
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.

The moment of inertia of a sphere of mass M and radius R about an axis passing through its
centre is $\\dfrac{2}{5} MR^2$. The radius of gyration of the sphere about a parallel axis to the above and tangent to the sphere is:

A gas mixture consists of 2 moles of O2 and 4 moles of Ar at temperature T. Neglecting all
vibrational modes, the total internal energy of the system is

A body of mass 6 kg is acted upon by a force which causes a displacement in it given
by x=$\\dfrac{t^2}{2}$ metre, where t is the time in second. The work done by the force in 2 seconds is