A magnetic needle has a magnetic moment of $$5 \times 10^{-2} \mathrm{~Am}^2$$ and moment of inertia $$8 \times 10^{-6} \mathrm{~kgm}^2$$. It has a period of oscillation of $$2 \mathrm{~s}$$ in a magnetic field $$\mathbf{B}$$. The magnitude of magnetic field is approximately?
A toroid has 500 turns per meter length. If it carries a current of $$2 \mathrm{A}$$, the magnetic energy density inside the toroid is
Consider the situation given in figure. The wire $$A B$$ is slid on the fixed rails with a constant velocity. If the wire $$A B$$ is replaced by a semicircular wire, the magnitude of the induced current will
The frequency of an alternating current is $$50 \mathrm{~Hz}$$. What is the minimum time taken by current to reach its peak value from rms value?