Radiation and Dual Nature of Matter — Physics STD 12 Science — Question

A molecule. of hydrogen contains two protons and two electrons. The nuclear force between these two protons is always neglected while discussing the behaviour of a hydrogen molecule. Why?

Draw a plot of potential energy of a pair of nucleons as a function of their separations. Mark the regions where the nuclear force is (i) attractive and (ii) repulsive. Write any two characteristic features of nuclear forces.

When a photon is emitted from an atom, the atom recoils. The kinetic energy of recoil and the energy of the photon come from the difference in energies between the states involved in the transition. Suppose, a hydrogen atom changes its state from n = 3 to n = 2. Calculate the fractional change in the wavelength of light emitted, due to the recoil.

A transverse wave of amplitude 0.50mm and frequency 100Hz is produced on a wire stretched to a tension of 100N. If the wave speed is 100m/s, what average power is the source transmitting to the wire?

A particle starts from the origin, goes along the X-axis to the point (20m, 0) and then returns along the same line to the point (-20m, 0). Find the distance and displacement of the particle during the trip.

If several forces act on a particle, the total torque on the particle may be obtained by first finding the resultant force and then taking torque of this resultant. Prove this. Is this result valid for the forces acting on different particles of a body in such a way that their lines of action intersect at a common point?

The temperature and relative humidity in a room are 300K and 20% respectively. The volume of the room is 50m³. The saturation vapour pressure at 300K is 3.3kPa. Calculate the mass of the water vapour present in the room.

A ball is dropped from a height. If it takes 0.200s to cross the last 6.00m before hitting the ground, find the height from which it was dropped. Take g = 10m/s².