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Question
A point charge produces an electric field of magnitude 5.0 NC−1 at a distance of 40 cm from it. What is the magnitude of the charge?
Solution
Given:
Magnitude of the electric field, E = 5.0 NC−1 at a distance, r = 40 cm = 0.4 m
Let the magnitude of the charge be q .
\[E = \frac{1}{4\pi \epsilon_0}\frac{q}{r^2}\]
\[ \Rightarrow 5 . 0 = 9 \times {10}^9 \times \frac{q}{\left( 0 . 4 \right)^2}\]
\[ \Rightarrow q = 8 . 9 \times {10}^{- 11} C\]
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