laws of thermal radiation

> Kirchhoffs law can be theoretically proved by the following 'thought experiment' Imagine a large enclosed space which is thermally isolated from the surroundings. Such an enclosure is called a uniform temperature enclosure or athermanous enclosure. Suppose that an ordinary body O and a perfectly black body B, both having the ..

The waves of thermal radiation are similar to the light-waves. The main properties of thermal radiation, which are also the properties of light, are as follows : (i) Thermal radiation can travel through vacuum : The thermal radiation from sun reaches the e..

Properties of Thermal Radiation

1. It travels through vacuum with the velocity of light (3 x 108 m/s) 2. It obeys the law of rectilinear propagation. 3. It undergoes reflection as well as refraction just as light. 4. ' It exhibits the phenomenon of interference, diffraction and polarisation. 5. It converts into heat when a body absorbs it. 6. It does not affect t..

thermal radiation wavelength

m . Measurements made at different temperatures by Lummer and Pringsheim (1899) yielded a set of curves like that of Fig. 5-2. The curves are similar in shape, but as the temperature increases, the height of the maximum increases and the position of the maximum is shifted in the direction of smaller wavelengths or greater frequencies. The to..

Thermal Radiation

Radiation is a process of transmission of heat from one place to another without the aid of any intervening medium. We receive heat from the sun by the process of radiation. Heat radiation can pass through vacuum just as light.Heat radiation from a body on account of its temperature is also called the..

Thermal Radiation

Introductio..

Kirchhoff's law of radiation

. If Ex and Ax are the emissive power and absorptive power of a black, body EL=dQ Ax dA" But absortive power Ax is unity for a black body ^ A, x But is a constant which shows that a body which radiates better should also absorb better. Therefore good absorbers are good emitters of radiation. u black body. (2) Applications of ki..

RADIATION NATURE OF THERMAL RADIATION

The energy emitted hy a body in the form of radiation by virtue of its temperature is called thermal radiation. This energy is emitted by all bodies above absolute zero and is also called radiant energy. The most powerful source of radiant energy is the Sun. Thermal radiation belongs ..

INTENSITY OF THE RADIATION

The intensity of radiation at a point varies inversely as the square of the distance. It oWys inverse square law i.e., if the distance is doubled, the intensity falls to one-fourth of its value. The intensityalso depends upon the strength of the source. If we focus our attention on a small range of wavelengths, ..

infrared radiations

radiations of smaller frequencies. Pointolite lamp is an arc struck between two tungsten electrodes enclosed in an evacuated bulb. It emits IR radiations of frequency nearly equal to 2 x 10 14 Hz. Gas lasers like C0 2 laser and He-Ne laser are used to obtain monochromatic /^-radiations of specific..

Explore More Pages

Recent Visited pages