JEE Advanced2010PhysicsElectrostaticsActual
A uniformly charged thin spherical shell of radius R carries uniform surface charge density of per unit area. It is made of two hemispherical shells, held together by pressing them with force F (see figure). F is proportional to
Options
- A1 ₀ ^2 R^2
- B1 ₀ ^2 R
- C1 ₀ ^2 R
- D1 ₀ ^2 R^2
Correct answer
A. 1 ₀ ^2 R^2
Step-by-step solution
Electrical force per unit area = 1 2 ₀ E^2 = 1 2 ₀ ( ₀ )^2= ^2 2 ₀ Projected area = R^2 net electrical force = ( ^2 2 ₀ ) ( R^2 ) In equilibrium, this force should be equal to the applied force. F= ^2 R^2 2 ₀ or F ^2 R^2 ₀ The correct option is (a).