The radius of a circular coil having 100 turns is 5 cm and a current of `0.5A` is flowing through this coil. If it is placed in a uniform magnetic field of stregth `0.001` T, then what torque will act on the coil, when the plane of the coil is parallel to the magnetic field,

Explanation

Number of turns 100
Current `I=0.5A`
Radius of the circular coil, `r=5 cm =5xx10^(-2)m`
`:.` Area of the coil, `A= pi r^(2)=3.14xx(5xx10^(-2))m^(2)`
Magnetic field intensity, `B=0.001T`.
Now torque on the current carrying coill due to magnetic field `tau =nBIAsin theta`
When the coil is paralle to the magnetic field then `theta=90^(@)`,
So, `tau=nBIA sin90^(@)`
`=100xx0.001xx0.5xx3.14xx25xx10^(-4)`
`=3.93xx10^(-4)N*m`