Question

The radii of two conducting sphere are $a$ and $b$. They are charged by equal amount then the ratio of electric filed intensity at its surfaces:

• A. $b^2:a^2$
• B. $1:1$
• C. $a^2:b^2$
• D. $b:a$

Answer 1

Answer: (A)

$b^2:a^2$

$b^2:a^2$

$q_A=q_B=q$

$\therefore E_A=\frac{qA}{4\pi {\epsilon }_0{a}^2}=\frac{q}{4\pi {\epsilon }_0{a}^2}......\left(1\right)$

$E_B=\frac{qB}{4\pi {\epsilon }_0{b}^2}=\frac{q}{4\pi {\epsilon }_0{b}^2}....\left(2\right)$

$\frac{E_A}{E_B}=\frac{q}{4\pi {\epsilon }_0{a}^2}\times \frac{4\pi {\epsilon }_0{b}^2}{q}=\frac{b^2}{a^2}=b^2:a^2$