The law which states that a variation in an electric field causes magnetic field, is
Radiation of wavelength $$300 \mathrm{~nm}$$ and intensity $$100 \mathrm{~W}-\mathrm{m}^{-2}$$ falls on the surface of a photosensitive material. If $$2 \%$$ of the incident photons produce photoelectron, the number of photoelectrons emitted from an area of $$2 \mathrm{~cm}^2$$ of the surface is nearly
Potential energy between a proton and an electron is given by $$U=\frac{K e^2}{3 R^3}$$, then radius of Bohr's orbit can be given by
A transistor is connected in common emitter configuration. The collector supply is $$8 \mathrm{~V}$$ and the voltage drop across a resistor of $$800 \Omega$$ in the collector circuit is $$0.5 \mathrm{~V}$$. If the current gain factor $$\alpha$$ is 0.96, then the base current is