Electrostatic Potential and Capacitance

An electric charge 10-6 is placed at origin (0,0) m of X − Y co-ordinate system. Two points P and Q are situated at ( 3, 3) m and ( 6,0) m respectively. The potential difference between the points P and Q will be :

1. 3 V
2. 6 V
3. 0 V
4. 3 V

The charge accumulated on the capacitor connected in the following circuit is (Given C = 150 ) [figure]

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :

1. Both (A) and (R) are correct and (R) is the correct explanation of (A)
2. (A) is correct but (R) is not correct
3. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
4. (A) is not correct but (R) is correct

The electric potential at the surface of an atomic nucleus (z=50) of radius 9 10-13 cm is 106 V.