The number of incorrect statement/s about the black body from the following is ____ (A) Emit or absorb energy in the form of electromagnetic radiation (B) Frequency distribution of the emitted radiation depends on temperature (C) At a given temperature, intensity vs frequency curve passes through a maximum value (D) The maximum of the intensity vs frequency curve is at a higher frequency at higher temperature compared to that at lower temperature
Answer: 0
Solution
A black body is an ideal object that can absorb and emit radiation of every wavelength, so the first statement is correct. The way the emitted energy is spread over frequency is settled by the temperature alone, as described by Planck's law, so the second statement is correct. At any one temperature the plot of intensity against frequency rises to a single maximum and then falls, so the third statement is correct. As the temperature is raised this maximum moves towards higher frequency, in keeping with Wien's displacement law, so the fourth statement is correct. Since all four statements are correct, the number of incorrect statements is zero.
