Question

Select the correct statement(s).

• A. The ideal body which emits and absorbs all frequencies is called a black body
• B. The exact frequency distribution of the emitted radiation from a black body depends upon its temperature
• C. In electromagnetic radiation the electric field and magnetic field are oscillating perpendicular to each other and also perpendicular to the direction of propagation.
• D. In vacuum, all types of electromagnetic radiations travel at the same speed

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A The ideal body which emits and absorbs all frequencies is called a black body
B The exact frequency distribution of the emitted radiation from a black body depends upon its temperature
C In electromagnetic radiation the electric field and magnetic field are oscillating perpendicular to each other and also perpendicular to the direction of propagation.
D In vacuum, all types of electromagnetic radiations travel at the same speed

a) The ideal body which emits and absorbs all frequencies is called a black body.

b) As temperature increases, the distribution of frequency (and energy) increases.

c) This is in accordance to Wien's displacement law. It states the frequency of the peak of the emission increases linearly with temperature.As temperature increases, the radiation of maximum intensity emitted is shifted from lower frequency to higher frequency.

d) All types of radiations have the same velocity $3\times {10}^8{\text{ms}}^{-1}$