Physics Test - ...

A domain in ferromagnetic iron is in the form of a cube of side length \(1 \mu \mathrm{m}\). Estimate the number of iron atoms in the domain and the maximum possible dipole moment and magnetisation of the domain. The molecular mass of iron is \(55 \mathrm{~g} / \mathrm{mole}\) and its density is \(7.9 \mathrm{~g} / \mathrm{cm}^{3}\). Assume that each iron atom has a dipole moment of \(9.27 \times 10^{-24} \mathrm{~A} \mathrm{~m}^{2}\):

A particle when thrown, moves such that it passes from same height at \(2\) s and \(10\) s, the height is:

A double-slit apparatus is immersed in a liquid of refractive index \(1.33\). It has slit separation of \(1\; mm\) and distance between the plane of slits and the screen is \(1.33 m\). The slits are illuminated by a parallel beam of light whose wavelength in air is \(6300 \mathring A\). What is the fringe width?

All electrons ejected from a surface by incident light of wavelength \(200 \mathrm{~nm}\) can be stopped before traveling \(1 \mathrm{~m}\) in the direction of a uniform electric field of \(4 \mathrm{NC}^{-1}\). The work function of the surface is:

Four identical particles of mass \(M\) are located at the corners of a square of side '\(a\)'. What should be their speed if each of them revolves under the influence of others' gravitational field in a circular orbit circumscribing the square?

A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads \(49 \mathrm{~N}\), when the lift is stationary. If the lift moves downward with an acceleration of \(5 \mathrm{~m} / \mathrm{s}^{2}\), the reading of the spring balance will be:

A particle starts S.H.M. from the mean position. Its amplitude is \(A\) and time period is \(T\). At the time when its speed is half of the maximum speed, its displacement \(y\) is:

A parallel beam of monochromatic light is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the first minimum of the diffraction pattern, the phase difference between the rays coming from the two edges of the slit is

A nucleus with mass number 242 and binding energy per nucleon as \(7.6 \mathrm{MeV}\) breaks into two fragment each with mass number 121. If each fragment nucleus has binding energy per nucleon as \(8.1 \mathrm{MeV}\), the total gain in binding energy is MeV.