JEE Advanced2011PhysicsMagnetic Effects of CurrentActual
An electron and a proton are moving on straight parallel paths with same velocity. They enter a semi-infinite region of uniform magnetic field perpendicular to the velocity. Which of the following statement(s) is/are true?
Options
- AThey will never come out of the magnetic field region
- BThey will come out travelling along parallel paths
- CThey will come out at the same time
- DThey will come out at different times
Correct answer
B. They will come out travelling along parallel paths
Step-by-step solution
r= m v B q or r m r_e aligned T_e & < T_p t_e & = T_e 2 aligned and or t_e < t_p Correct options are (b) and (d). Note In JEE 2011, official answer key, correct options were given bc, bd, bcd, here student should realise that both the electron and proton enter the magnetic field at the same time or at different times. Analysis of Question (i) Question is simple. (ii) In the situation given above particle will never complete the circle unless magnetic field is all around.