A point charge of $+ 2; μ C$ is placed at the origin. What is the magnitude of the electric field at a point 0.5 m on the y‑axis?

easy MCQ 1 mark Class 12 · Physics · Electric Charges and Fields

$7.20 \times 1 0^{4}; N/C$
$4.50 \times 1 0^{4}; N/C$
$9.00 \times 1 0^{4}; N/C$
$1.80 \times 1 0^{5}; N/C$

Answer

7.20 \times 1 0^{4}; N/C

The correct answer is $7.20 \times 1 0^{4}; N/C$ — $E = 8.988 \times 1 0^{9} \times 8 \times 1 0^{- 6} = 7.19 \times 1 0^{4}; N/C a pp r o x 7.20 \times 1 0^{4}; N/C$ .

Step-by-step solution

$k = 8.988 \times 1 0^{9}; N\cdotm^{2} /C^{2}$ , $Q = 2 \times 1 0^{- 6}; C$ , $r = 0.5; m$ .
$E = d i s pl a y s t y l e \frac{k Q}{r ^{2}} = \frac{8.988 \times 1 0 ^{9} \times 2 \times 1 0 ^{- 6}}{( 0.5 ) ^{2}}$ .
$E = 8.988 \times 1 0^{9} \times 8 \times 1 0^{- 6} = 7.19 \times 1 0^{4}; N/C a pp r o x 7.20 \times 1 0^{4}; N/C$ .

Common mistake: Using

1/ r

instead of

1/ r^{2}

Concept tested: Electric field of a point charge

Published 18 September 2026 · How this solution was prepared and checked

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A point charge of +2;μC is placed at the origin. What is the magnitude of the electric field at a point 0.5 m on the y‑axis?

Step-by-step solution

A point charge of $+ 2; μ C$ is placed at the origin. What is the magnitude of the electric field at a point 0.5 m on the y‑axis?