​​​When a metallic surface is illuminated with radiation of wavelength \(\lambda\), the stopping potential is \({V}\). If the same surface is illuminated with radiation of wavelength \(2\lambda\), the stopping potential is \(\frac{{V}}{4}\). The threshold wavelength for the metallic surface is:
1. \(5\lambda\)
2. \(\frac{5}{2} \lambda\)
3. \(3\lambda\)
4. \(4\lambda\)

A particle is dropped from a height \(H.\) The de-Broglie wavelength of the particle as a function of height is proportional to:
1. \(H\)
2. \(H^{1/2}\)
3. \(H^{0}\)
4. \(H^{-1/2}\)

An electron (mass \(m\)) with an initial velocity \(\overrightarrow{\mathrm{v}}=\mathrm{v}_0 \hat{\mathrm{i}}\) $\stackrel{}{\mathrm{}}$(\(\mathrm{v}_0>0\)) is in an electric field \(\overrightarrow{\mathrm{E}}=-\mathrm{E}_0 \hat{\mathrm{i}}\)$({\mathrm{}}_{}$\(E_o\)=constant\(>0\)). Its de-Broglie wavelength at time \(t\) is given by:

According to Einstein's photoelectric equation, the graph between the kinetic energy of photoelectrons ejected and the frequency of incident radiation is:

1.		2.
3.		4.

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 \(\frac{d}{2}\), then the number of electrons emitted per second will be: 
1. same
2. four times
3. two times
4. one-fourth

J.J. Thomson's cathode-ray tube experiment
demonstrated that:
 

The work function of caesium is \(2.14~\text{eV}\). The wavelength of incident light if the photocurrent is brought to zero by a stopping potential of \(0.60~\text{V}\) will be:
1. \(454~\text{nm}\)
2. \(440~\text{nm}\)
3. \(333~\text{nm}\)
4. \(350~\text{nm}\)