Consider the shown circuit. The capacitors $C_1$ and $C_2$ have capacitances $2 \mu \mathrm{~F}$ and $8 \mu \mathrm{~F}$, respectively. The switch can connect point $X$ to either $Y$ or $Z$. Initially $X Y$ is connected until the capacitor is fully charged by the battery. Then the switch connects $X$ and $Z$, and the final charges on Cl and C 2 are $Q_1$ and $Q_2$, respectively. What is the value of the ratio $\frac{Q_2}{Q_1+Q_2}$ ?

Two monochromatic sources emit light at wavelengths $\lambda$ and $\lambda / 2$. The stopping potentials for a photosensitive material using these two sources are found to be 1 V and 3 V , respectively. What is the work function of the material?