A child stands on a weighing machine inside a lift. When the lift is going down with acceleration $\mathrm{g} / 3$, the machine shows a reading 20 N . When the lift goes upwards with acceleration $\mathrm{g} / 3$, the reading would be ( $\mathrm{g}=$ gravitational acceleration)

The equivalent capacitance between plates ' A ' and ' B ' ( A -area of each plate, d-separation between plates) ( $\varepsilon_0$ - permittivity of free space) is

Which of the following transitions in hydrogen atom emit photons of highest frequency? ( $\mathrm{n}=$ principle quantum number)

Water rises up to height ' $x$ ' in a capillary tube immersed vertically in water. When the whole arrangement is taken to a depth ' $d$ ' in a mine, the water level rises up to height Y . If R is the radius of the earth then the ratio $\mathrm{Y}: \mathrm{x}$ is