A body of mass \(2\,kg\) makes an elastic collision with a second body at rest and continues to move in the original direction but with one fourth of its original speed. What is the mass of the second body? ................ \( \mathrm{kg}\)

A circular disc has radius \(R_1\) and thickness \(T_1\). Another circular disc made of the same material has radius \(R_2\) and thickness \(T_2\). If the moment of inertia of both discs are same and \(\frac{R_1}{R_2}=2\) then \(\frac{T_1}{T_2}=\frac{1}{\alpha}\).The value of \(\alpha\) is __________ .

A square loop of side \(2a\) and carrying current I is kept in \(xz\) plane with its centre at origin. A long wire carrying the same current I is placed parallel to \(z-\)axis and passing through point \((0, b , 0),( b >> a ) .\) The magnitude of torque on the loop about \(z-\)ax is will be

A transparent block A having refractive index \(\mu=1.25\) is surrounded by another medium of refractive index \(\mu=1.0\) as shown in figure. A light ray is incident on the flat face of the block with incident angle \(\theta\) as shown in figure. What is the maximum value of \(\theta\) for which light suffers total internal reflection at the top surface of the block?

Density of water at \(4^{\circ} C\) and \(20^{\circ} C\) are \(1000 kg / m ^3\) and respectively. The increase in internal energy of 4 kg water when it is heated from \(4{ }^{\circ} C\) to \(20^{\circ} C\) is _________ J.
(Specific heat capacity of water \(=4.2 KJ / kg\). and 1 atmospheric pressure \(=10^5 Pa\) )

From the top of a tower, a ball is thrown vertically upward which reaches the ground in \(6 \,s\). A second ball thrown vertically downward from the same position with the same speed reaches the ground in \(1.5\, s\). A third ball released, from the rest from the same location, will reach the ground in........ \(s\).

Two open organ pipes of length \(60 \mathrm{~cm}\) and \(90 \mathrm{~cm}\) resonate at \(6^{\text {th }}\) and \(5^{\text {th }}\) harmonics respectively. The difference of frequencies for the given modes is _______ \(\mathrm{Hz}\). (Velocity of sound in air \(=333 \mathrm{~m} / \mathrm{s}\) )

A coil of circular cross-section having \(1000\, turns\) and \(4\, cm^2\) face area is placed with its axis parallel to a magnetic field which decreases by \(10^{-2}\, Wb\, m^{-2}\) in \(0.01\, s\). The \(e.m.f.\) induced in the coil is....\(mV\)

The following bodies, \((1)\) a ring \((2)\) a disc \((3)\) a solid cylinder \((4)\) a solid sphere, of same mass \(m\) and radius \(R\) are allowed to roll down without slipping simultaneously from the top of the inclined plane. The body which will reach first at the bottom of the inclined plane is ........... [Mark the body as per their respective numbering given in the question]

If the wavelength of the first member of Lyman series of hydrogen is \(\lambda\). The wavelength of the second member will be _______.

A spherical interface lens of radius \(R\) separates two media of refractive indices \(1\) and \(1.4\) respectively as shown in the figure below. A point source is placed at a distance of \(4R\) in front of spherical interface. The magnitude of the magnification of point source image is _______.

For a free body diagram shown in the figure, the four forces are applied in the ' \(x\) ' and ' \(y\) ' directions. What additional force must be applied and at what angle with positive \(x\)-axis so that the net acceleration of body is zero?