The electric potential at a point in an electric field is $8×10^4 V$. The work done to bring a point charge $5×10^{-9} C$ from infinity to this point in the field is

$4×10^{-4} J$

The correct answer is Option (2) → $4×10^{-4} J$

Given:

Electric potential, $V = 8 \times 10^{4} \ \text{V}$

Charge, $q = 5 \times 10^{-9} \ \text{C}$

Work done is

$W = qV$

$W = (5 \times 10^{-9})(8 \times 10^{4})$

$W = 40 \times 10^{-5}$

$W = 4 \times 10^{-4} \ \text{J}$

Answer: $4 \times 10^{-4} \ \text{J}$