Question

An electric dipole is placed at an alignment angle of 30º with an electric field of 2 × 10^5 N /C. It experiences a torque equal to 8 N m. The charge on the dipole if the dipole length is 1 cm​

Answer 1

2mC

Here dipole moment , p=lq=(2/100)q=0.02q

Now, torque , τ=pEsinθ

or 4=(0.02q)(2×10

5

)sin30

or q=200×10

−5

C=2mC