Every question from past board papers on Torque on magnetic dipole in uniform field, newest paper first. Open any question for its full worked answer.
In a uniform magnetic field of 0.049 T, a magnetic needle performs 20 complete oscillations in 5 seconds as shown. The moment of inertia of the needle is \(9.8\times10^{-6}\) kg m\(^2\). If the magnitude of magnetic moment of the needle is \(x\times10^{-5}\) Am\(^2\); then the value of 'x' is :
If \(\theta_1\) and \(\theta_2\) be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip \(\theta\) is given by :
A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by 60° is \(W\). Now the torque required to keep the magnet in this new position is
