According to Plank's quantum theory, hypothesis, and radiation law:
1. False. Energy is emitted by a vibrating particle only when it changes from one energy state to another.
2. true. energy is propagated in the form of radiation or photons with energy = h ν, where ν is the frequency of the emitted wave
3. False. According to Plank's quantum theory, energy states of the particle oscillating, energy emitted and energy absorbed are all in discrete multiples of a quanta = h ν. A fraction of this quantum is not possible to emit/absorb.
4. True. It has been observed that black body radiant energy at the same temperature, first increases with wavelength to a maximum and then it decreases.