If the de-Broglie wavelength of a neutron at a temperature of $77^{\circ} \mathrm{C}$ is $\lambda$, then the de-Broglie wavelength of the neutron at a temperature of $1127^{\circ} \mathrm{C}$ is

If Planck's constant is $6.63 \times 10^{-34} \mathrm{Js}$, then the slope of a graph drawn between cut-off voltage and frequency of incident light in a photoelectric experiment is

The graph given in the figure shows the variation of photo current $(I)$ and the applied voltage ( $V$ ) for two different materials and for two different intensities of the incident radiations. Then the curves which represent the same material are

Radiations of wavelength 400 nm incidents on a photosensitive material of work function 2.2 eV . The stopping potential is nearly