The electric field intensity near a conducting surface having uniform surface charge density ' $\sigma$ ' is given by ( $\varepsilon_0=$ permittivity of free space)

The excess pressure inside first soap bubble is three times that of a second soap bubble. The ratio of volumes of the first to second bubble

A particle performs S.H.M. of amplitude 'A' and wavelength ' $\lambda$ ', Then the velocity of the wave (V) and the maximum particle velocity (v) are related as

The figure shows two masses ' $m$ ' and ' $M$ ' connected by a light string that passes through ${ }_a$ small hole ' $O$ ' at the centre of the table. Mass ' $m$ ' is moved round in a horizontal circle with ' $O$ ' as the centre. The frequency with which ' $m$ ' should be revolved so that ' $M$ ' remains stationary is

( $\mathrm{g}=$ gravitational acceleration)