Question

A positive charge moves in west and is deflected towards north the direction of magnetic field

Answer 1

Answer:

Here the direction of positively charged alpha particle is towards west this implies the direction of current is also towards west and the direction of magnetic force is towards north. Hence, according to Fleming's left hand rule, the direction of magnetic field will be upwards.

Explanation:

Answer 2

By right hand thumb rule..

put your thumb in the direction of velocity (in West direction )

and your fingers are in direction of magnetic field (in North direction)

now your palm shows the direction of magnetic force (which is downword).

hope it helps.