Question

Light of intensity I is incident normally on a perfectly reflecting plate of area A kept in a gravity free space. If the photons strike the plate symmetrically and initially the spring was at its natural length, find the maximum compression in the springs –

• A. $\frac{IA}{KC}$
• B. $\frac{2IA}{3KC}$
• C. $\frac{3IA}{KC}$
• D. $\frac{4IA}{3KC}$

Answer 1

Answer: (D)

$\frac{4IA}{3KC}$

Answer 2

Force = $\frac{2IA}{C}$

F × x = $\left( \frac{1}{2}Kx^{2} \right)$ × 3

$\frac{2IA}{C}$ × x = $\frac{1}{2}$ × Kx² × 3

x = $\frac{4}{3}\frac{IA}{KC}$