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An electromagnetic wave transports linear momentum as it travels through space. If an electromagnetic wave transfers a total energy U to a surface in time t, then total linear momentum delivered to the surface is $\text{p}=\frac{\text{U}}{\text{c}}.$ When an electromagnetic wave falls on a surface, it exerts pressure on the surface. ln 1903, the American scientists Nichols and Hull succeeded in measuring radiation pressures of visible light where other had failed, by making a detailed empirical analysis of the ubiquitous gas heating and ballistic effects.

1. The pressure exerted by an electromagnetic wave of intensity I $(Wm^{-2})$ on a non-reflecting surface is (c is the velocity of light).

1. $\text{Ic}$
2. $\text{Ic}^2$
3. $\frac{\text{I}}{\text{c}}$
4. $\frac{\text{I}}{\text{c}^2}$

2. Light with an energy flux of $18\frac{\text{W}}{\text{cm}^2}$ falls on a non-reflecting surface at normal incidence. The pressure exerted on the surface is:

1. $3\frac{\text{N}}{\text{m}^2}$
2. $2\times10^{-4}\frac{\text{N}}{\text{m}^2}$
3. $6\frac{\text{N}}{\text{m}^2}$
4. $6\times10^{-4}\frac{\text{N}}{\text{m}^2}$

3. Radiation of intensity $0.5Wm^{-2}$ are striking a metal plate. The pressure on the plate is:

1. $0.166 \times 10^{-8}Nm^{-2}$
2. $0.212 \times 10^{-8}Nm^{-2}$
3. $0.132 \times 10^{-8}Nm^{-2}$
4. $0.083 \times 10^{-8}Nm^{-2}$

4. A point source of electromagnetic radiation has an average power out-put of 1500W. The maximum value of electric field at a distance of 3m from this source $($in $Vm^{-1})$ is:

1. $500$
2. $100$
3. $\frac{500}{3}$
4. $\frac{250}{3}$

5. The radiation pressure of the visible light is of the order of,

1. $10^{-2}\frac{\text{N}}{\text{m}^2}$
2. $10^{-4}\frac{\text{N}}{\text{m}}$
3. $10^{-6}\frac{\text{N}}{\text{m}^2}$
4. $10^{-8}\text{N}$