All electrons ejected from a metallic surface by incident light of wavelength $400 \,nm$ travelled $1 \,m$ in the direction of a uniform electric field of $2 \,N/C$ and came to rest. The work function of the surface is (in $\,eV$)

The work functions of Silver and Sodium are $4.6 \ eV$ and $2.3 \ eV$,respectively. The ratio of the slope of the stopping potential versus frequency plot for Silver to that of Sodium is :

The frequency and the intensity of a beam of light falling on the surface of a photoelectric material are both increased by a factor of two. This will:

Assertion : In the process of photoelectric emission, all emitted electrons do not have the same kinetic energy.
Reason : If radiation falling on the photosensitive surface of a metal consists of different wavelengths, then the energy acquired by electrons absorbing photons of different wavelengths shall be different.

Why maximum kinetic energy of a photoelectron cannot be negative?

The stopping potential for a source of wavelength $4000\, \mathring{A}$,when kept at a distance of $10\, \text{cm}$,is $1.5\, \text{V}$. If now the distance of the source is increased to $20\, \text{cm}$,then the stopping potential will be ............... $\text{V}$.