JEE Main20206 Sep 2020Evening ShiftPhysicsElectrostaticsActual
Two identical electric point dipoles have dipole have dipole moments p → 1 = p i ^ and p → 2 = − p i ^ and are held on the x -axis at distance ' a ' from each other. When released, they move along the x -axis with the direction of their dipole moments remaining unchanged. If the mass of each dipole is ' m ', their speed when they are infinitely far apart is :
Options
- AP a 1 πε 0 ma
- BP a 1 2 πε 0 ma
- CP a 2 πε 0 ma
- DP a 3 2 πε 0 ma
Correct answer
B. P a 1 2 πε 0 ma
Step-by-step solution
k i + u i = k f + u f 0 - 2 k p r 3 p 2 · cos 180 ° = 1 2 m v 2 + 1 2 m v 2 + 0 m v 2 = 2 k p 1 p 2 r 3 ⇒ θ = 2 k p 1 p 2 m r 3 p 1 = p 2 = p & r = a v = p a 1 2 π ϵ 0 ma