A man standing in a truck moving with constant velocity throws a ball vertically into air, ball falls
A charge of $$+1 \mathrm{C}$$ is moving with velocity $$\vec{V}=(2 \mathrm{i}+2 \mathrm{j}-\mathrm{k}) \mathrm{ms}^{-1}$$ through a region in which electric field $$\vec{E}=(\mathrm{i}+\mathrm{j}-3 \mathrm{k}) \quad \mathrm{NC}^{-1}$$ and magnetic field $$\vec{B}=(\mathrm{i}-2 \mathrm{j}+3 \mathrm{k}) \mathrm{T}$$ are present. The force experienced by the charge is
Modulus of rigidity of an incompressible liquid is
In a hydrogen atom, if electron is replaced by a particle which is 40 times heavier but has the same charge, then, the ratio of the radius of the first excited state of a normal hydrogen atom to the ground state of the above atom is