Question

calculate the force on a straight wire 11 cm long carrying a current of 12 A when the wire is in a 200μT magnetic field perpendicular to the wire​

Answer 1

ANSWER

The magnetic field B, due to a long infinite straight current carrying (I) wire at a distance r is given by:

          B=2πμ0.rI

Given: I=100A,r=10cm=0.1m

Hence, B=2π4π×10−7.0.1100=2×10−4T

Now, according to Right hand thumb rule, the direction of this magnetic field at point P will be inwards to the plane of paper. A magnetic field of 1.0×10−4T is already there and both the fields are perpendicular to each other. 

Therefore resultant field strength at point P will be:

       B′=(2×10−4)2+(1.0×10