Q 1 :    

An electric dipole is placed at an angle of 30° with an electric field of intensity 2×105N C-1. It experiences a torque equal to 4 Nm. Calculate the magnitude of charge on the dipole, if the dipole length is 2 cm.        [2023]
 

  • 4 mC

     

  • 2 mC

     

  • 8 mC

     

  • 6 mC

     

(2)

Given, angle, θ=30°,

Electric field intensity, E=2×105 N C-1

τ=4 Nm, Dipole length, l=2 cm=0.02 m

τ=pEsinθ=(ql)Esinθ

    q=τElsinθ=42×105×0.02×12=2 mC

 



Q 2 :    

An electric dipole is placed at an angle of 30° with an electric field intensity 2×105N C-1. It experiences a torque equal to 4 N m. The charge on the dipole, if the dipole length is 2 cm, is             [2016]
 

  • 8 mC

     

  • 2 mC

     

  • 5 mC

     

  • μC

     

(2)

Here, θ=30°,E=2×105N C-1,τ=4Nm

l=2 cm=0.02 m, q=? ; τ=pEsinθ=(ql)Esinθ

   q=τElsinθ=42×105×0.02×12

           =42×103=2×10-3C=2 mC