When 0.25$$\mathop A\limits^o $$ X-Rays strike a material, the photoelectrons from the $$K$$ shell are observed to more in a circle of radius $$23 \mathrm{~mm}$$ in magnetic field of $$4 \times 10^{-2}$$ tesla active perpendicularly to the direction of emission of photoelectrons. What is the Binding energy of $$K$$ shell electrons?
A common emitter amplifier has a voltage gain of 50 an input impedance of 100 $$\Omega$$ and an output impedance of 400 $$\Omega$$. The power gain of the amplifier is
In an electron gun the potential difference between the filament and plate is $$4000 \mathrm{~V}$$. What will be the velocity of electron emitting from the gain?
A man of mass $m$ starts falling towards a planet of mass $$M$$ and radius $$R$$. As he reaches near to the surface, he realizes that will pass through a small role in the planet. As he enters the role, we sees that the planet is really made of two pieces a spherical shell of negligible thickness of mass $$3 M / 4$$ and a point mass $$M / 4$$ at the centre. Change in the force of gravity experienced by the man is