question_answer

A stream of electrons and protons are directed towards a narrow slit in a screen (see figure). The intervening region has a uniform electric field E (vertically downwards) and a uniform magnetic field B (out of the plane of the figure) as shown. Then

A)  electrons and protons with speed \[\frac{|E|}{|B|}\]will pass through the slit

B)  protons with speed \[|E|/|B|\] will pass through the slit, electrons of the same speed will not                

C)  neither electrons nor protons will go through the slit irrespective of their speed                         

D)  electrons will always be deflected upwards  irrespective of their speed     

Correct Answer: C

Solution :

 Neither electrons nor protons will go through the slit irrespective of their speed. And electrons will always be deflected upwards irrespective of their speed. So, [c] and [d] are correct options.