NTA Abhyas JEE Main2020PhysicsElectrostaticsPractice
An electric dipole is situated in an electric field of uniform intensity E whose dipole moment is p and moment of inertia is I . If the dipole is displaced slightly from the equilibrium position, then the angular frequency of its oscillations is
Options
- ApE I 1/2
- BpE I 3/2
- CI pE 1/2
- Dp IE 1/2
Correct answer
A. pE I 1/2
Step-by-step solution
  τ = P × E = P E sin θ .... (i) - P E sin θ = I α [ I is the moment of inertia and α the angular acceleration] Since displacement is small sin θ = ∼ θ ∴ I α = - PE θ ⇒ α = - PE I θ The angular frequency of oscillation is given by ω = PE I The potential energy is lowest when the dipole moment is aligned with the field and highest when the two are antialigned.