The mass and the diameter of a planet are three times the respective values for the Earth. The period of oscillation of simple pendulum on the Earth is 2 s. The period of oscillation of the same pendulum on the planet would be :

A metal ball of mass 0.1 kg is heated upto 500^oC and dropped into a vessel of heat capacity 800 JK^–1 and containing 0.5 kg water. The initial temperature of water and vessel is 30^oC. What is the approximate percentage increment in the temperature of the water? [Specific Heat Capacities of water and metal are, respectively, 4200 Jkg^–1 and 400 Jkg^–1 K^–1

A 27 mW laser beam has a cross-sectional area of 10 mm². The magnitude of the maximum electric field in this electromagnetic wave is given by :
[Given permittivity of space $$ \in $$₀ = 9 $$ \times $$ 10^–12 SI units, Speed of light c = 3 $$ \times $$ 10⁸ m/s]

In a hydrogen like atom, when an electron jumps from the M-shell to the L-shell, the wavelength of emitted radiation is $$\lambda $$. If an electron jumps from N-shell to the L-shell, the wavelength of emitted radiation will be: