CBSE Class 12 · 2023 · ElectrostaticsMultiple Choice

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The magnitude of the electric field due to a point charge object at a distance of 4.0 m is 9 N/C. From the same charged object the electric field of magnitude 16 N/C will be at a distance of

(A)1 m
(B)2 m
(C)3 m✓ Correct
(D)6 m

Answer: (C)

Solution

For a point charge

E \propto 1/ r^{2}

, so:

E_{1} r_{1}^{2} = E_{2} r_{2}^{2}

r_{2} = r_{1} E_{1} / E_{2} = 4.0 9/16

r_{2} = 4.0 \times \frac{3}{4}

r_{2} = 3.0 m

CBSE Class 12 Board · 2023 · Single correct option

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