Question

A ring of charge with radius 0.5 m having a 0.02 m gap, carries a charge of +1 C. The field at the centre is–

• A. 2.31 × 10⁴ N/C
• B. 2.31 × 10⁸ N/C
• C. 1.6 × 10⁴ N/C
• D. 1.6 × 10⁸ N/C

Answer 1

Answer: (B)

2.31 × 10⁸ N/C

Answer 2

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+

\ E = $\frac { \mathrm { kdq } } { \mathrm { R } ^ { 2 } }$

=$\frac { 1 } { 4 \pi \varepsilon _ { 0 } }$ $\frac { \lambda \mathrm { d } \ell } { \mathrm { R } ^ { 2 } }$=$\frac { 1 } { 4 \pi \varepsilon _ { 0 } }$ $\left( \frac { \mathrm { q } } { 2 \pi \mathrm { R } } \right)$ $\frac { \mathrm { d } \ell } { \mathrm { R } ^ { 2 } }$

= $\frac { 9 \times 10 ^ { 9 } \times 1 \times 0.02 } { 2 \times 3.14 \times ( 0.5 ) ^ { 3 } }$