A radiation of energy 'E' falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (c=velocity of light)

1. E/c

2. 2E/c

3. 2E/c²

4. E/c²

Which of the following figures represents the variation of the particle momentum and the associated de-Broglie wavelength?

1.		2.
3.		4.

Light with a wavelength of $500$ nm is incident on a metal with a work function of  $2.28~\text{eV}.$ The de Broglie wavelength of the emitted electron will be:
1. $<2.8 \times 10^{-10}~\text{m}$
2. $<2.8 \times 10^{-9}~\text{m}$
3. $\geq 2.8 \times 10^{-9}~\text{m}$
4. $<2.8 \times 10^{-12}~\text{m}$

Light with an energy flux of $25\times 10^{4}~\text{Wm}^{-2}$ falls on a perfectly reflecting surface at normal incidence. If the surface area is $15~\text{cm}^2$, then the average force exerted on the surface is:
1. $1.25\times 10^{-6}~\text{N}$
2. $2.5\times 10^{-6}~\text{N}$
3. $1.2\times 10^{-6}~\text{N}$
4. $3.0\times 10^{-6}~\text{N}$

What will be the percentage change in the de-Broglie wavelength of the particle if the kinetic energy of the particle is increased to $16$ times its previous value?
1. $25$
2. $75$
3. $60$
4. $50$