Two mercury drops of radii $ r $ and $ 2r $ merge to form a bigger drop. The surface energy released in the process is nearly (Surface tension of mercury is } $S$ and take $9^{2/3} = 4.326$)
Two charges +q and -q, each 1 $\mu$C are arranged as shown in the figure. If x = 2 cm and y = 3 cm then potential difference ($V_A - V_B$) is
If Young’s modulus of elasticity is $Y = \dfrac{2mg l^2}{5b t e}$, where ‘g’ is the acceleration due to gravity, ‘m’ is the mass, ‘l’ is the length, ‘b’ is the breadth, ‘t’ is the thickness and ‘e’ is the elongation, then the value of $k$ is
The de Broglie wavelength of the most energetic photoelectrons emitted from a photosensitive metal of work function \( \phi \), when light of frequency \( \nu \) is incident on it, is \( \lambda \). Then find \( \nu \) in terms of Planck’s constant \( h \), mass of electron \( m \), and other constants.