Question

There is uniform magnetic field between large parallel plates of a capacitor having separation d and potential difference V. A positively charge particle is projected very near to positive plate parallel to it with velocity u. Due to magnetic and electric field resultant motion of particle would be helical. Then mark the CORRECT statement(s).

Answer 1

Answer:

A) 23

B) 69

C) 55

D) 42

B) is the highest

Answer 2

• There is a potential difference V between two large parallel plates separated by a distance d.
• In region 2 ,  to the right side of plate D there is a uniform magnetic field B pointing perpendicularly and is pointed out of the paper.
• An electron charge –e and mass m is released from rest at plate C passes through a hole in plate D into region 2 .

Therefore we get ,  

we know that

• a = $\frac{qe}{m}$
• d=$\frac{1}{2} \frac{at^{2} }{}$

Inserting the value of a into d ,

       d =    $\frac{1}{2} \frac{qe}{m} t^{2}$

⇒ $t^{2}$ =$\frac{d2m}{qe}$

⇒t = $\sqrt{\frac{d2m}{qe} }$

The time taken by partical will be $\sqrt{\frac{d2m}{qe} }$

we also know that V=ed

Inserting the value of e into the equation,

⇒ t =$\sqrt{\frac{d^{2} 2m}{qV} }$