KCET2018PhysicsElectrostatics
The magnitude of point charge due to which the electric field ( 30 ~cm ) away has the magnitude ( 2 ~N C⁻¹ ) will be
Options
- A( 2 10⁻¹¹ C )
- B( 3 10⁻¹¹ C )
- C( 5 10⁻¹¹ C )
- D( 9 10⁻¹¹ C )
Correct answer
A. ( 2 10⁻¹¹ C )
Step-by-step solution
Electric field due to a point charge is [ E= 1 4 ₀ q r² ] Given, [ array l E=2 N C⁻¹ ; r=30 ~cm =30 10⁻² m ; 1 4 ₀ =9 10⁹ 2=9 10⁹ q (30 10⁻² )² q= 2 (30 10⁻² )² 9 10⁹ =2 10⁻¹¹ C array ] Therefore, magnitude of charge will be ( 2 10⁻¹¹ C )