To increase the current sensitivity of a moving coil galvanometer by $$25 \%$$, its resistance is increased so that the new resistance becomes twice its initial resistance. By what factor does the voltage sensitivity change?
A uniformly charged solid sphere of radius $$\mathrm{R}$$ has potential $$\mathrm{V}_0$$ (measured with respect to infinity) on its surface. For this sphere the equipotential surfaces with potentials $$\frac{3 \mathrm{~V}_0}{2}, \frac{\mathrm{V}_0}{1}, \frac{3 \mathrm{~V}_0}{4}$$ and $$\frac{\mathrm{V}_0}{4}$$ have radius $$\mathrm{R}_1, \mathrm{R}_2, \mathrm{R}_3$$ and $$\mathrm{R}_4$$ and respectively, then
Energy required for moving a body of mass $$\mathrm{m}$$ from a circular orbit of radius 3R to a higher orbit of radius 4R around the earth is.
The shortest wavelengths of Paschen, Lymen and Balmer series are in the ratio