Q 1 :    

The value of electric potential at a distance of 9 cm from the point charge 4×10-7C is

(Given that 14πε0=9×109Nm2C-2)                                                                [2024]
 

  • 4×102 V

     

  • 44.4 V

     

  • 4.4×105 V

     

  • 4×104 V

     

(4)

r=9 cm=9×10-2 m

q=4×10-7C

As, V=14πε0qr=9×109×4×10-79×10-2=4×104V



Q 2 :    

If a conducting sphere of radius R is charged. Then the electric field at a distance r(r>R) from the centre of the sphere would be, (V = potential on the surface of the sphere)        [2023]
 

  • rVR2

     

  • R2Vr3

     

  • RVr2

     

  • Vr

     

(3)

Consider a sphere of radius 'R' and charge 'Q'.

Given, r>R

Potential, V=KQR                                      ...(i)

Electric field, E=KQr2                                ...(ii)

Using value of Q=VRK in equation (ii),

E=Kr2×VRK=VRr2