If temperature of Sun $$=6000 \mathrm{~K}$$, radius of Sun is $$7.2 \times 10^5 \mathrm{~km}$$, radius of Earth $$=6000 \mathrm{~km}$$ and distance between Earth and Sun $$=15 \times 10^7 \mathrm{~km}$$. Find intensity of light on Earth.

Assertion : In both radioactivity and photoelectric effect electrons may be ejected.

Reason : In photoelectric effect and radioactivity emission occurs only of unstable elements.

The graph between the energy log E of an electron and its de-Broglie wavelength log $$\lambda$$ will be

Assertion : Photoelectric effect can take place only with an electron bound in the atom.

Reason : Electron is a fermion whereas proton is a boson.