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
Two identical moving coil galvanometers have $$10 \Omega$$ resistance and full-scale deflection at $$2 \mu \mathrm{A}$$ current. One of them is converted into a voltmeter of range $$10 \mathrm{~mV}$$ and the other into an ammeter of range $$1 \mathrm{~mA}$$ using appropriate resistors. The ratio of resistance of the converted voltmeter to that of the ammeter is