# How does the power per unit area emitted by a black body vary with its temperature?

### How does the power per unit area emitted by a black body vary with its temperature?

The wavelength at which the radiation is strongest is given by Wien’s displacement law, and the Powerful total issued by unit area is given by the Stefan-Boltzmann law. So as the temperature increases, the color of the glow changes from red to yellow to white to blue.

### How to calculate thermal radiation?

In a small wavelength interval, the emitted flux Femi has the following expression: h = 6.63 x 10-34 Js: Planck’s constant; kB = 1.38 x 10-23 J/s Boltzmann constant; c = 3, m/s speed of light; λ: wavelength; T: Opaque body temperature.

### How does the wavelength of maximum intensity change when the temperature of the black body increases?

In increasing the black body temperatureI’intensity radiation mean increased. At the same time, the values ​​of wavelengths the most emitted tend to decrease, gradually approaching the visible. Towards a temperature of approximately 1000°K, a red light is emitted by the body.

### How does the wavelength vary with temperature?

It stipulates that the wave length of the maximum emission is inversely proportional to its temperature. More the temperature of the blackbody increases, the more the maximum of existance moves towards the short wavelengths.

### How to calculate the wavelength of maximum intensity?

Ex: the temperature of the human body is 37.5 °C, or about 310 K. We therefore have: λmax = (2.90 × 10-3) / 310 = 9.35 × 10- nm. the maximum emission from the human body is therefore in the infrared.

### How to calculate power?

1 The power or the number of watts (watt) corresponds to the product obtained by multiplying the intensity by the voltage. It’s simple ! … 2 For a current of 3 amps (3 A) and a voltage of 110 volts (V), you calculate the product () to obtain 330 watts (W). … 3 This is why power is sometimes expressed in volt-amperes. …

### How to calculate the power of a receiver?

From current and voltage. The power received by a receiver is equal to the product of the intensity which crosses it by the voltage between its terminals. In the case of ohmic conductors, all of this power received is dissipated in the form of heat.

### How to calculate the power of a current?

Generally, the formula is written as follows: W = A × V . For a current of 3 amps (3 A) and a voltage of 110 volts (V), you calculate the product () to get 330 watts (W). The formula is P = V = 330 W, where P denotes power.

### What is the difference between power and electrical energy?

Electrical power and energy Course. Summary. The power consumed by an electrical device depends on the voltage between its terminals and the current flowing through it. Electrical energy depends on the power consumed and the duration of use, it is this which is billed to the consumer.