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Question
A particle of mass 1 g and charge 2.5 × 10−4 C is released from rest in an electric field of 1.2 × 10 4 N C−1. How much is the work done by the electric force on the particle during this period?
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Solution
Given:
Charge of the particle, q = 2.5 × 10−4 C
Initial velocity, u = 0
Electric field intensity, E = 1.2 × 104 N/C
Mass of the particle, m = 1 g = 10−3 kg
Distance travelled, s = 40 cm = 4 × 10−1 m
Work done by the electric force,
\[W = F_e s = 3 \times 4 \times {10}^{- 1} \]
\[ = 12 \times {10}^{- 1} \] J = 1 . 20 J
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