In a mixture of H - He$$^+$$ gas (He$$^+$$ is singly ionized He atom), H atoms and He$$^+$$ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He$$^+$$ ions (by collisions). Assume that the Bohr model of atom is exactly valid.
The wavelength of light emitted in the visible region by He$$^+$$ ions after collisions with H atoms is
In a mixture of H - He$$^+$$ gas (He$$^+$$ is singly ionized He atom), H atoms and He$$^+$$ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He$$^+$$ ions (by collisions). Assume that the Bohr model of atom is exactly valid.
The ratio of the kinetic energy of the $$n=2$$ electron for the H atom to that of He$$^+$$ ion is
A small block of mass M moves on a frictionless surface of an inclined plane, as shown in figure. The angle of the incline suddenly changes from 60$$^\circ$$ to 30$$^\circ$$ at point B. The block is initially at rest at A. Assume that collisions between the block and the incline are totally inelastic (g = 10 m/s$$^2$$).
The speed of the block at point B immediately after it strikes the second incline is
A small block of mass M moves on a frictionless surface of an inclined plane, as shown in figure. The angle of the incline suddenly changes from 60$$^\circ$$ to 30$$^\circ$$ at point B. The block is initially at rest at A. Assume that collisions between the block and the incline are totally inelastic (g = 10 m/s$$^2$$).
The speed of the block at point C, immediately before it leaves the second incline is