2004 AIPMT Electrostatic Potential and CapacitanceWork Done by Electric Field Easy Question 70 of 76 in Electrostatic Potential and Capacitance

A bullet of mass 2 g is having a charge of 2 $\mu C$. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of 10 m/s ?

A 50 kV
B 5 V
C 50 V
D 5 kV

The answer is A.

Solution

Work done by the electric field on the charge = gain in kinetic energy.
Use $qV_{acc} = \dfrac{1}{2}mv^2$
$m = 2$ g $= 2 \times 10^{-3}$ kg, $q = 2\ \mu C = 2 \times 10^{-6}$ C, $v = 10$ m/s
$\dfrac{1}{2}mv^2 = \dfrac{1}{2} \times 2 \times 10^{-3} \times 10^2 = 0.1$ J
$V = \dfrac{0.1}{2 \times 10^{-6}} = 5 \times 10^4$ V
$V = 50$ kV

Concept Accelerating potential and kinetic energy

Electrostatic Potential and Capacitance in past papers

76 questions from this chapter have appeared across 27 exam years.