Question

Statement-1 : When ultraviolet light is incident on a photocell, its stopping potential is $v_0$ and the maximum kinetic energy of the photo electrons is $K_{max}$ . When the ultraviolet light is replaced by X-rays, $K_{max}$increases but $v_0$ , decreases.
Statement -2: Photo electrons are emitted with speeds ranging from zero to a maximum value.Below a certain negative voltage $V_0$ ,no photons are emitted in a photocell

• A. Statement-1 is True,statement-2 is True;Statement-2 is correct explanation for statement-1
• B. Statement-1 is True,Statement-2 is True; Statement-2 is NOT a correct explanation for statement-1
• C. Statement-1 is True,Statement-2 is False
• D. Statement-1 is False, Statement-2 is True

Answer 1

The correct option is D Statement-1 is False, Statement-2 is True

The stopping potential is independent of its intensity. If q is the charge on the electron and $v_0$ is the stopping potential, then $K_{max}=q{v}_0$. so as$K_{max}$ increases $v_0$ also increases when X-ray applied because the stopping potential is independent of its intensity. so statement 1 is false.
Generally,photo electrons are emitted with speeds ranging from zero to a maximum value and some there cut off voltage to emit photon. so statement 2 is true.