Question

The wavelength range of thermal radiation is
(A) from $4000\,\mathop A\limits^o $to $7000\mathop A\limits^o $
(B) from$7700\mathop A\limits^o $ to $4 \times {10^6}\mathop A\limits^o $
(C) from${10^6}\mathop A\limits^o $ to ${10^8}\mathop A\limits^o $
(D) from$4 \times {10^{ - 12}}\mathop A\limits^o $ to $4 \times {10^8}\mathop A\limits^o $

Answer 1

Hint
The electromagnetic radiation that is emitted from all types of matter is called thermal radiation. The thermal radiation that is emitted from matter belongs normally to a certain range of wavelengths that is from $7700 \times {10^{ - 10}}m$ to $4 \times {10^{ - 4}}m$.

Complete step by step answer
Thermal radiation is a type of electromagnetic radiation. This thermal radiation is the emission of radiation by a body as a result of its temperature. The radiation is called thermal radiation as this radiation is the result of the change in the thermal state of the matter.
The wavelength range of the thermal radiation emitted by the matter, that is, the electromagnetic radiation for a series of temperature, except for a 0 temperature is $0.1\,\mu m$to$100\,\mu m$. This wavelength range of the thermal radiation includes some of the rays of electromagnetic radiation, those are, UV (some part), visible (whole part) and infrared (whole part). This range of the wavelength of the thermal radiation in terms of the Angstrom unit can be expressed as $7700\mathop A\limits^o $ to $4 \times {10^6}\mathop A\limits^o $.
$\therefore $ Therefore, the wavelength range of the thermal radiation is from $7700\mathop A\limits^o $ to $4 \times {10^6}\mathop A\limits^o $, thus, option (B) is correct.

Additional Information
Planck’s law describes the amount of radiation emitted by a black body at a specific wavelength. The Planck’s curve is a graph obtained by plotting the emissive power for a black body versus the wavelength for a series of temperatures. The conversion of Angstrom to the meter unit is done as, $1\,^\circ A = 0.0000000001{\text{ }}m = 1 \times {10^{ - 10}}\,m$.

Note
The thermal radiation is emitted from all kinds of matter having a temperature that is greater than absolute zero. A few examples of the thermal radiation are the infrared radiations which are emitted by the animals and the cosmic microwave background.