00:01
Hello students.
00:03
In this question we are given that which of the following statements are true about the motion of a particle in a magnetic field.
00:11
So if you have a particle moving in a magnetic field and there are very statements given about that motion, then which of these statements are true? so we'll start with the very first one.
00:23
The first one says that a charged particle moving in a magnetic field experiences four perpendicular to its velocity and the direction of the magnetic field vector.
00:31
And this is actually a true statement because we know that the force acting on a charge particle moving in a magnetic field is given by f is equal to qv cross b.
00:45
This is the force acting on a charge particle moving in a magnetic field and we can say about the direction of the force that it is perpendicular to the plane containing v vector and b vector where both v and b are also perpendicular to each other.
01:24
So what we can say about this kind of force acting on a charged particle moving in a magnetic field is thus.
01:31
The force is perpendicular to the plane containing the velocity vector and the magnetic field vector.
01:37
And in this plane, both the vectors are also equally perpendicular to each other.
01:41
So yes, a charged particle moving in a magnetic field does experience a force perpendicular.
01:45
Perpendicular to the velocity and the direction of magnetic field vector.
01:49
So simultaneously we can cut this thing out.
01:51
This is an incorrect statement that the force exerted on a charged particle moving in a magnetic field is always perpendicular to its direction of motion.
01:59
It is not always perpendicular to the direction of motion only, but it is perpendicular to the direction of motion and the magnetic field.
02:07
Both.
02:09
Now we'll see the second statement that a current carrying wire placed in a magnetic field experiences a force.
02:15
This statement is also correct if we have a wire let's assume that this is a wire carrying current i then this current would experience a force if it is placed in a magnetic field b vector then it will experience a force f is equal to i l cross b this is the bior savats law and it says that the force acting on a current carrying wire is mathematically equal to i l cross b so the second statement is also correct.
02:51
The third statement says that two parallel carrying current carrying wires always repel each other or two parallel current carrying wires always attract each other.
03:03
So both of them are actually incorrect statements and we're going to tell you and we're going to explain to you how exactly that does does that work.
03:11
Let's let's first take the case of two parallel current carrying wires, two parallel current carrying wires always attract each and two parallel current carrying wires always repel each other, it is not true because if we have two wires, let's assume this is wire a and this is wire b, then two parallel wires attract each other when the current is flowing through them in the same direction.
03:40
If the current is flowing through both the wires in the same direction, then we say that they attract each other.
03:48
Whereas if the current is flowing in the opposite directions, that means that it is flowing.
03:52
In this way and this way in this wire, then they repel each other.
03:57
Then they repel each other.
04:00
So two current, parallel current carrying wires do not always attract or repel each other.
04:06
It depends upon the direction of current that is flowing through the wire.
04:10
We can explain here briefly how it works.
04:13
So if we have two wires, let's assume this is two wires.
04:17
This is wire a and this is wire b.
04:20
And in wire a, the current is flowing in the upper direction and also in wire b the current is flowing in the upward direction...