The current conduction in a discharge tube is due to:
1.  electrons only
2.  +ve ions and –ve ions
3.  –ve ions and electrons
4.  +ve ions and electrons

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

Light of wavelength \(3000 ~{\mathring{\mathrm{A}}}\) in Photoelectric effect gives electron of maximum kinetic energy \(0.5 ~\text{eV}\). If the wavelength changes to \(2000 ~{\mathring{\mathrm{A}}}\) then the maximum kinetic energy of emitted electrons will be:

If the K.E. of an electron and a photon is the same, then the relation between their de-Broglie wavelength will be:

1. ${\lambda }_{ph}$ $<$ ${\lambda }_e$

2. ${\lambda }_{ph}$ $=$ ${\lambda }_e$

3. ${\lambda }_{ph}$ $>$ ${\lambda }_e$

4. ${\lambda }_{ph}$ $=2$ ${\lambda }_e$

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. $6.63\times {10}^{-34}$ $\mathrm{J}/\mathrm{s}$

2. $6.63\times {10}^{-34}$ $\mathrm{kg}-{\mathrm{m}}^2/\mathrm{s}$

3. $6.63\times {10}^{-34}$ $\mathrm{kg}-{\mathrm{m}}^2$

4. $6.63\times {10}^{-34} J/s$

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