If a light of amplitude A and wavelength λ is incident on a metallic surface, then the saturation current flow is proportional to (assume cut-off wavelength = ${\lambda }_0$):

1. $A^2,$ $if$ $\lambda$ $>$ ${\lambda }_0$

2. $A^2,$ $if$ $\lambda$ $<$ ${\lambda }_0$

3. $A,$ $if$ $\lambda$ $>$ ${\lambda }_0$

4. $A,$ $if$ $\lambda$ $<$ ${\lambda }_0$

The total energy of an electron is \(3.555~\text{MeV}\). Its kinetic energy will be:
1.  \(3.545~\text{MeV}\)
2.  \(3.045~\text{MeV}\)
3.  \(3.5~\text{MeV}\)
4.  none of the above

The value of Planck's constant is:
1. \(6.63\times 10^{-34}~\text{J/s}\)
2. \(6.63\times 10^{-34}~\text{kg-}\text{m}^2\text{/s}\)
3. \(6.63\times 10^{-34}~\text{kg-}\text{m}^2\)
4. \(6.63\times 10^{-34}~\text{J-s}^2\)

If particles are moving with the same velocity, then the de-Broglie wavelength is maximum for:
1. proton
2. \(\alpha\text-\)particle
3. neutron
4. \(\beta\text-\)particle

When ultraviolet rays strike a metal plate, the photoelectric effect does not occur. It occurs by the incidence of:

1. Infrared rays

2. X-rays

3. Radio wave

4. Lightwave

Which of the following is not the property of cathode rays:

Which one among the following shows the particle nature of light?
1. Photoelectric effect
2. Interference
3. Refraction
4. Polarisation

A photo-cell is illuminated by a source of light, which is placed at a distance \(d\) from the cell. If the distance becomes \(\dfrac{d}{2}\), then the number of electrons emitted per second will be: 
1. same
2. four times
3. two times
4. one-fourth