Physics Test - ...

In an \(LCR\) circuit capacitance is changed from \(C\) to \(2C\). For the resonant frequency to remain unchanged, the inductance should be changed from \(L\) to:

Which is the correct diagram of a half-wave rectifier?

A particle of mass m carrying charge \(+q_{1}\) is revolving around a fixed charge \(-q_{2}\) in a circular path of radius r. Calculate the period of revolution of the particle.

When photons of energy hv fall on an aluminium plate (of work function E₀), photoelectrons of maximum kinetic energy K are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be:

Consider the geometry shown in the figure of a silicon step junction:

The uniform impurity doping concentrations of \(\mathrm{N}_{\mathrm{a}}=5 \times 10^{15} \mathrm{~cm}^{-3}\), \(\mathrm{n}_{\mathrm{i}}=1.5 \times 10^{10} \mathrm{~cm}^{-3}\).

If the applied voltage \(V_{a}=\frac{1}{2} V_{b i}\) then, the value of \(V_{a}\) will be:

When the energy of the incident radiation is increased by \(20 \%\). The kinetic energy of the photoelectrons emitted from a metal surface increased from \(0.5 \mathrm{eV}\) to \(0.8 \mathrm{eV}\). The work function of the metal is:

Find the amount of work done in rotating a dipole of dipole moment \(3 \times 10^{-3} {~cm}\) from its position of stable equilibrium to the position of unstable equilibrium, in a uniform electric field of intensity \(10^{4} {NC}^{-1}\).

A screw gauge gives the following readings whenused to measure the diameter of a wire:

Main scale reading = 0 mm

Circular scale reading = 52 divisions

Given that 1 mm on main scale corresponds to 100divisions on the circular scale. The diameter of thewire from the above data is:

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:

What is the escape speed from the surface of the Earth equal to?

If two unequal resistors connected in parallel then:

The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?

A satellite that is revolving around the earth has a minimum distance from earth equal to \(r_{1}\) and a maximum distance of \(r_{2}\), then the time period of the satellite will be?

The flux of electric field through closed conducting loop changes with time as \(\phi_{E}=\left(10 t^{2}-20 t+5\right) V m\) then, the value of displacement current into medium of \(\epsilon_{0}\) at time \(t=1 {sec}\) is:

Light rays from an object fall on a surface and get reflected in a completely diffused manner. What can you say about the nature of image of the object?