Question

A block of mass in and charge q is placed on a smooth horizontal table which terminates in a vertical wall at a distance d the block . A horizontal electric field E towards right is switched on. Assuming elastic collision, find time period of the resulting oscillatory motion.

• A. $\sqrt{\frac{8dm}{qE}}$
• B. $\sqrt{\frac{4dm}{qE}}$
• C. $\sqrt{\frac{2dm}{qE}}$
• D. None of these

Answer 1

Answer: (A)

$\sqrt{\frac{8dm}{qE}}$

Answer 2

a = qE/m and d = 1/2 at²

or t = $\sqrt{\frac{2d}{a}} = \sqrt{\frac{2dm}{qE}}$

Time period T = 2t = 2$\sqrt{\frac{2dm}{qE}}$ = $\sqrt{\frac{8dm}{qE}}$