For a hydrogen atom, the ratio of the largest wavelength of Lyman series to that of the Balmer series is

In the following circuit, the reading of the ammeter will be

$($ Take Zener breakdown voltage $=4 \mathrm{~V})$

A cubic block of mass $m$ is sliding down on an inclined plane at $60^{\circ}$ with an acceleration of $\frac{g}{2}$, the value of coefficient of kinetic friction is

Match the List I with List II

Choose the correct answer from the options given below: