A proton and a deutron $$(q=+\mathrm{e}, m=2.0 \mathrm{u})$$ having same kinetic energies enter a region of uniform magnetic field $$\vec{B}$$, moving perpendicular to $$\vec{B}$$. The ratio of the radius $$r_d$$ of deutron path to the radius $$r_p$$ of the proton path is:

The temperature of a gas is $$-78^{\circ} \mathrm{C}$$ and the average translational kinetic energy of its molecules is $$\mathrm{K}$$. The temperature at which the average translational kinetic energy of the molecules of the same gas becomes $$2 \mathrm{~K}$$ is :

The excess pressure inside a soap bubble is thrice the excess pressure inside a second soap bubble. The ratio between the volume of the first and the second bubble is:

A spherical ball of radius $$1 \times 10^{-4} \mathrm{~m}$$ and density $$10^5 \mathrm{~kg} / \mathrm{m}^3$$ falls freely under gravity through a distance $$h$$ before entering a tank of water, If after entering in water the velocity of the ball does not change, then the value of $$h$$ is approximately:

(The coefficient of viscosity of water is $$9.8 \times 10^{-6} \mathrm{~N} \mathrm{~s} / \mathrm{m}^2$$)