If a dipole of dipole moment 'p' is kept in a uniform electric field 'E' then the cross product (p x E) is equal to _______________ the dipole.

CONCEPT:

• Electric dipole: When two equal and opposite charges are separated by a small distance then this combination of charges are called as electric dipole.
  • The multiplication of charge and the distance between them is called as electric dipole moment.

Dipole moment (P) = q × d

Where q is charge and d is distance between two charge particles.

Torque on electric dipole:

∴ τ = force × arms of couple

τ = F × 2asinθ = (qE) × 2asinθ

τ = (q × 2a)E sinθ 

τ = pE sinθ

EXPLANATION:

∴ From the above, it is clear that the torque acting on a dipole moment p placed in an electric field E is .

So option 2 is correct.