A long straight wire AB carries a current of 4 A. A proton P travels at parallel to the wire 0·2 m from it and in a direction opposite to the current as shown in the figure. Calculate the force which the magnetic field due to the current carrying wire exerts on the proton. Also specify its direction.
The magnetic field at point P due to
Current carrying straight wire AB,
Where 'I' is current
'r' is the distance at point P from the wire.
Now,
Force acting on moving proton in the magnetic field;
Where, 'B' is magnetic field
'q' is charge
'v' is velocity
from equation (i) putting the value of B in equation (ii), we get
We have given that;
Therefore:-