Physics Test - ...

In Photoelectric effect

A photon is

If maximum velocity with which an electron can be emitted from a photo cell is 3.75×10⁸cms⁻¹ then stopping potential is

Fluorescence is

Suppose you are given a chance to repeat the alpha-particle scattering experiment using a thin sheet of solid hydrogen in place of the gold foil. (Hydrogen is a solid at temperatures below 14 K.) What results do you expect?

The control rods in a nuclear reactor

A sample of radioactive material contains 10¹⁸ atoms. The half life of the material is 2 days, then the activity of the sample is

Force on current-carrying conductor:

(A) F = I(L × B).

(B) Between parallel conductors defines ampere.

(C) Attractive for same direction currents.

(D) Zero for perpendicular currents.

Magnetic dipole moment:

(A) For current loop, m = I A.

(B) Torque τ = m × B.

(C) Potential energy U = -m · B.

(D) Independent of loop shape.

Moving coil galvanometer:

(A) Measures current.

(B) Current sensitivity is θ/I.

(C) Converted to ammeter by shunt.

(D) Converted to voltmeter by high resistance in parallel.