An electron accelerated by a potential difference ' $V$ ' has de-Broglie wavelength ' $\lambda$ '. If the electron is accelerated by a potential difference ' 9 V ', its de-Broglie wavelength will be

The maximum velocity of the photoelectrons emitted by a metal surface is $9 \times 10^5 \mathrm{~m} / \mathrm{s}$. The value of ratio of charge (e) to mass (m) of the photoelectron is $1.8 \times 10^{11} \mathrm{C} / \mathrm{kg}$. The value of stopping potential in volt is