The work done in placing a charge of 8 × 10−18 coulomb on a condenser of capacity 100 micro-farad is

Question

The work done in placing a charge of 8 × 10−18 coulomb on a condenser of capacity 100 micro-farad is (A) 16 × 10−32 joule (B) 3.2 × 10−26 joule (C) 4 × 10−10 joule (D) 32 × 10−32 joule

Tardigrade Admin · Accepted Answer

Required work done is w=(1/2) (Q2/C2) =(1/2)×((8×10-18)2/10-4)=32×10-32 J

Q. The work done in placing a charge of $8 \times 1 0^{- 18}$ coulomb on a condenser of capacity 100 micro-farad is

$16 \times 1 0^{- 32}$ joule

$3.2 \times 1 0^{- 26}$ joule

$4 \times 1 0^{- 10}$ joule

$32 \times 1 0^{- 32}$ joule

Required work done is $w = \frac{1}{2} \frac{Q ^{2}}{C ^{2}}$
$= \frac{1}{2} \times \frac{( 8 \times 1 0 ^{- 18} ) ^{2}}{1 0 ^{- 4}} = 32 \times 1 0^{- 32} J$

Q. The work done in placing a charge of 8×10−18 coulomb on a condenser of capacity 100 micro-farad is

16×10−32 joule

3.2×10−26 joule

4×10−10 joule

32×10−32 joule