Question

When the sun rays are incident at an angle of ${60}^0$ then intensity is $I$. What will be the intensity if the sun rays are incident at ${30}^o$?

• A. $\frac{I}{\sqrt{3}}$
• B. $\sqrt{3}I$
• C. $3I$
• D. $\frac{I}{3}$

Answer 1

The correct option is B $\sqrt{3}I$

The intensity of sun rays that making angle $\theta$ is equal to $I_0\cos \theta$, where $I_0$ is the intensity of the sun rays if it incident perpendicularly to the surface.

Now, when the rays making angle ${30}^{\circ }$, intensity will be $I\left(\cos 30/\cos 60\right)=\sqrt{3}I$