00:01
All right, in this question, we have to find the force which is acting on this positive charged particle when it enters into a magnetic field.
00:06
Remember that the force on a magnet on a charged particle on a magnetic field is given by q times v cross b.
00:12
So basically it's qvb sign of theta where theta is the angle between v and b.
00:17
Clearly v and b are in the same direction.
00:19
So what is the angle between them? that's zero, right? so and what is sign zero? that's zero.
00:25
So the force in this case is just zero.
00:29
In case two, they are actually at 90 degrees.
00:33
So how is the direction given? we are just interested in the direction.
00:36
The direction is given by right -hand rule.
00:38
So we take our right -hand because the force is q times v -cross -b...