Question

The electrons in the beam of a television tube move horizontally from south to north. The vertical component of the earths magnetic field points down. The electron is deflected towards

• A. east
• B. no deflection
• C. west
• D. north to south

Answer 1

Answer: (C)

west

$F=q\left(v\times B\right)$

Consider, $v$ is acting in the south to north i.e. in the $+y$ direction. The vertical component of B is in downwards direction i.e. $-z$. Hence $v\times B$ will be in $-x$ direction. So, the beam will get deflected towards west.