Question

An electron gun T emits electron accelerated by a potential difference U in a vacuum in the direction of the line a as shown in figure. Target M is placed at a distance d as shown in figure. Find the magnetic field perpendicular to the plane determine by line a and the point M in order that electron hit the target M –

• A.
• B. $\sqrt { \frac { 2 \mathrm { Um } _ { \mathrm { e } } } { \mathrm { e } } }$
• C. $\sqrt { \frac { 2 U m _ { e } } { e } } \frac { \operatorname { Sin } \alpha } { d }$
• D. $\frac { \operatorname { Sin } \alpha } { d }$

Answer 1

Answer: (A)

Answer 2

BeV = … (1)

Also, r = $\frac { d } { 2 \sin \alpha }$ … (2)

Kinetic energy of electron = eU …(3)

From (1), (2), (3)

B =