Question

A square of side 20 cm is enclosed by a surface of sphere of 80 cm radius. Square and sphere have the same centre. Four charges + 2 × 10^–6C, – 5 × 10^{– 6}C, – 3 × 10^{– 6}C, +6 × 10^{– 6}C are located at the four corners of a square, then out going total flux from spherical surface in N–m²/C will be

• A. Zero
• B. (16 π) × 10^{– 6}
• C. (8π) × 10^–6
• D. 36π × 10^–6

Answer 1

Answer: (A)

Zero

Answer 2

Since charge enclosed by Gaussian surface is

$\varphi_{enc.} = (2 \times 10^{- 6} - 5 \times 10^{- 6} - 3 \times 10^{- 6} + 6 \times 10^{- 6}) = 0$ so $\varphi = 0$