KCET2023PhysicsMagnetic Effects of Current
A positively charged particle q of mass m is passed through a velocity selector. It moves horizontally righward without deviation along the line y= 2 m v q B with a speed v . The electric field is vertically downwards and magnetic field is into the plane of paper. Now, the electric field is. switched off at t=0 . The angular momentum of the charged particle about origin O at t= m q B is
Options
- Am E^2 q B^3
- Brac 4 m^2 E^2 q B^3
- CZero
- Dm E^3 q B^2
Correct answer
B. rac 4 m^2 E^2 q B^3
Step-by-step solution
Radius of the circle, r= m v B q Equation of line, y= 2 m v B q =2 R Time pariod, T= 2 m B q t= m B q = T 2 Angular momentum of charged particle about origin aligned L & =m v y+m v y=2 m v y & =2 m v 2 R & =4 m v m v B q = 4 m^2 v^2 B q aligned From velocity selector, aligned & v= E B L & = 4 m^2 E^2 q B^3 aligned