When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2I what is the number of emitted electrons and their maximum kinetic energy?

1.	N and 2T	2.	2N and T
3.	2N and 2T	4.	N and T

A helium-neon laser produces monochromatic light of a wavelength of 667 nm. The power emitted is 9 mW. The average number of photons arriving per second on average at a target irradiated by this beam is:

1. $9\times {10}^{17}$

2. $3\times {10}^{16}$

3. $9\times {10}^{15}$

4. $3\times {10}^{19}$

Waves are associated with matter only:

A particle which has zero rest mass and non-zero energy and momentum must travel with a speed:

If the following particles are moving at the same velocity, then which among them will have the maximum de-Broglie wavelength?
1. Neutron               

2. Proton

3. $\mathrm{\beta }$-particle             

4. $\mathrm{\alpha }$-particle

What is the momentum of a photon in an X-ray beam of 10^-10 meter wavelength?

The energy of a quanta of frequency ${10}^{15}$ Hz and $\mathrm{h}=6.6\times {10}^{-34}\mathrm{ J}-\sec$ will be:

1. $6.6\times {10}^{-19}$ $\mathrm{J}$

$\mathrm{}$2.$6.6\times {10}^{-12}$ $\mathrm{J}$

3. $6.6\times {10}^{-49}$ $\mathrm{J}$

$\mathrm{}$4.$6.6\times {10}^{-41}$ $\mathrm{J}$

The number of photo-electrons emitted per second from a metal surface increases when:

A photon of energy 3.4 eV is incident on a metal having a work function of 2 eV. The maximum K.E. of photo-electrons is equal to:

A photocell is receiving light from a source placed at a distance of 1 m. If the same source is placed at a distance of 2 m, then the ejected electron: