A ball of mass 1 g and charge 10-8 C moves from a point A, where potential is 600 V to the point B where potential is zero. Velocity of the ball at the point B is 20 cms -1. The velocity of the ball at the point A will be

Question

A ball of mass 1 g and charge 10-8 C moves from a point A, where potential is 600 V to the point B where potential is zero. Velocity of the ball at the point B is 20 cms -1. The velocity of the ball at the point A will be (A) 22.8 cms -1 (B) 228 cms -1 (C) 16.8 cms -1 (D) 168 cms -1

Tardigrade Admin · Accepted Answer

By using, (1/ 2) m ( v12 - v22 ) = QV ( 1/ 2) × 10 - 3 [ v12 - ( 0.2)2 ] = 10 - 8 ( 600 - 0) v1 = 22.8 cms - 1.

Q. A ball of mass 1 g and charge $1 0^{- 8}$ C moves from a point A, where potential is 600 V to the point B where potential is zero. Velocity of the ball at the point B is 20 $c m s^{- 1}$ . The velocity of the ball at the point A will be

22.8 $c m s^{- 1}$

228 $c m s^{- 1}$

16.8 $c m s^{- 1}$

168 $c m s^{- 1}$

By using, $\frac{1}{2} m (v_{1}^{2} - v_{2}^{2}) = Q V$
$\frac{1}{2} \times 1 0^{- 3} [v_{1}^{2} - (0.2)^{2}] = 1 0^{- 8} (600 - 0)$
$v_{1} = 22.8 c m s^{- 1}$ .

Q. A ball of mass 1 g and charge 10−8 C moves from a point A, where potential is 600 V to the point B where potential is zero. Velocity of the ball at the point B is 20 cms−1. The velocity of the ball at the point A will be

22.8 cms−1

228 cms−1

16.8 cms−1

168 cms−1