JEE Main2010PhysicsElectrostaticsActual
A thin semi-circular ring of radius r has a positive charge q distributed uniformly over it. The net field E at the centre O is
Options
- Aq 4 ^2 ₀ r^2 j
- B- q 4 ^2 ₀ r^2 j
- C- q 2 ^2 ₀ r^2 j
- Dq 2 ^2 ₀ r ^2 j
Correct answer
C. - q 2 ^2 ₀ r^2 j
Step-by-step solution
Linear charge density = ( q r )E= d E (- j )= K d q r ^2 (- j ) E = K r ^2 qr r ~d (- j )= K r ^2 q ₀^ (- j )= q 2 ^2 ₀ r ^2 (- j )