A paramagnetic sample shows a net magnetisation of $$8 \mathrm{Am}^{-1}$$ when placed in an external magnetic field of $$0.6 \mathrm{~T}$$ at a temperature of $$4 \mathrm{~K}$$. When the same sample is placed in an external magnetic field of $$0.2 \mathrm{~T}$$ at a temperature of $$16 \mathrm{~K}$$, the magnetisation will be
The ratio of magnetic field at the centre of a current carrying circular coil to its magnetic moment is $$x$$, if the current and the radius both are doubled. The new ratio will become
In a permanent magnet at room temperature
A rod of length $$2 \mathrm{~m}$$ slides with a speed of $$5 \mathrm{~ms}^{-1}$$ on a rectangular conducting frame as shown in figure. There exists a uniform magnetic filed of $$0.04 \mathrm{~T}$$ perpendicular to the plane of the figure. If the resistance of the rod is $$3 \Omega$$. The current through the rod is