$A$ photon of energy $5.5 \ eV$ strikes a surface that emits photoelectrons with a maximum kinetic energy of $4.0 \ eV$. The stopping potential for these electrons is ............ $V$.

If the frequency of light falling on a photosensitive material doubles, which of the following is true?

When two monochromatic lights of frequency $v$ and $\frac{v}{2}$ are incident on a photoelectric metal,their stopping potentials are $\frac{V_{s}}{2}$ and $V_{s}$ respectively. The threshold frequency for this metal is:

In a photoelectric experiment, the wavelength of the light incident on the metal is changed from $200 \, nm$ to $400 \, nm$. The decrease in the stopping potential is close to [Use $hc = 1240 \, eV \cdot nm$ where $h$ is Planck's constant and $c$ is the velocity of light]. (in $ \, V$)

Photoelectric effect is observed on a surface for frequencies $5.5 \times 10^8 \text{ MHz}$ and $4.5 \times 10^8 \text{ MHz}$. If the ratio of the maximum kinetic energy of the emitted photoelectrons is $1:5$,then the threshold frequency for the metal surface is:

According to Einstein's photoelectric equation,the plot of the maximum kinetic energy of the emitted photoelectrons from a metal versus the frequency of the incident radiation gives a straight line whose slope: