Correct Answer - Option 2 : 9J
CONCEPT:
- The amount of work done in moving a unit positive charge in an electric field from infinity to that point without accelerating the charge against the direction of the electric field.
- The electrostatic potential is given by
\(\Rightarrow V = \frac{W}{q}\)
- The electrostatic potential due to a point charge is given by
\(\Rightarrow V = \frac{Kq}{r}\) \([\because K = \frac{1}{4\pi\epsilon_{0}}]\)
Where W = Work , q = charge, and r = distance
CALCULATION :
Given - q1 = 5μC, r = 5cm =5× 10-2 m,q2 = 10μC
- The electric potential due to 5μC at a distance of 5 cm away from it is
\(\Rightarrow V = \frac{9\times 10^{9}\times 5\times 10^{-6}}{5\times 10^{-2}} = 9\times 10^{5} V\)
- The work done in moving the charge of 10 μC from infinity to P is
\(\Rightarrow W = V\times q = 9\times 10^{5}\times 10\times 10^{-6}=9 J\)
- Hence option 2 is the answer