CBSE
2022
Class Class 12 · Physics
3 Marks · Short
✅ Verified
Calculate the potential at the centre of a square ABCD of each side √2 m due to charges 2, −2, −3 and 6 µC at the four corners.
✅ Answer & Solution
Given:
• Side of square = √2 m
• Charges: q₁ = 2 µC, q₂ = −2 µC, q₃ = −3 µC, q₄ = 6 µC
Step 1 — Distance from Corner to Centre:
Diagonal of square = √2 × side = √2 × √2 = 2 m
r = diagonal / 2 = 2/2 = <b>1 m</b>
Step 2 — Net Charge:
ΣQ = (2 − 2 − 3 + 6) µC = <b>3 µC = 3 × 10⁻⁶ C</b>
Step 3 — Potential at Centre:
V = k × ΣQ / r
= (9 × 10⁹ × 3 × 10⁻⁶) / 1
= <b>2.7 × 10⁴ V</b>
∴ <b>Potential at centre = 27,000 V = 2.7 × 10⁴ V</b>
✅ Verified by Super Admin