Question

A metal wire is bent into a circle of radius 10 cm .It is given a charge of 200 C, which spreads on it uniformly . Calculate the electric potential at it's centre

Answer 1

Given :

• Metal wire is bent into a circle or radius (R) = 10 cm or ${\sf 10 \times 10^{-2}\:m}$
• Charge (Q) = 200 C

To Find :

• Electric Potential at it's centre

Formula Used :

$\bullet\underline{\boxed{\sf V =9 \times 10^9 \dfrac{Q}{R}}}$

Solution :

$\implies{\sf V = \dfrac{9 \times 10^9 \times 200}{10 \times 10^{-2}} }$

$\implies{\sf V = \dfrac{9 \times 2 \times 10^{11}}{0.1} }$

$\implies{\bf V = 18 \times 10^{12}\: volt }$

Answer :

Electric Potential at the centre is ${\bf 18 \times 10^{12}\:volt}$

➞ Extra Info . -

$\bullet$ It is scalar quantity

$\bullet$ Unit :- V = J/C = volt

$\bullet$ In presence of a medium Potential decreases and becomes ${\sf \dfrac{1}{\epsilon_r}}$ times of its free space value

Answer 2

Hey there !

You should remeber a formula to crack this question for a hollow shell in case of Metals

Formula used KQ/r

electric potential = 9×10^9 × 200 /10×10^-2

= 1.8 × 10^13V