Q. A conductor has been given a charge $- 3 \times 10^{- 7}C$ by transferring electrons. Mass increase (in kg) of the conductor and the number of electrons added to the conductor are respectively
A) $2 \times 10^{- 16}\ and\ 2 \times 10^{31}$
B) $5 \times 10^{- 31}\ and\ 5 \times 10^{19}$
C) $3 \times 10^{- 19}\ and\ 9 \times 10^{16}$
D) $2 \times 10^{- 18}\ and\ 2 \times 10^{12}$
Explanation
(d) Number of electrons added to the conductor
$n = \frac{q}{e}$
$= \frac{- 3 \times 10^{- 7}}{1.6 \times 10^{- 19}} = 1.8 \times 10^{12}$
Mass increase of the conductor
$= 1.8 \times 10^{12} \times 9.1 \times 10^{- 31}$
$\ \approx 20 \times 10^{- 19} = 2 \times 10^{- 18}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.