Advertisements
Advertisements
प्रश्न
The wavelength range of thermal radiation is
(A) from 4000 Å to 7000 Å
(B) from 7700 Å to 4 x 106 Å
(C) from 106 Å to 108 Å
(D) from 4 x 10-12 Å to 4 x 108 Å
उत्तर
(b) from 7700 Å to 4 x 106 Å
APPEARS IN
संबंधित प्रश्न
Draw a neat labelled diagram for Ferry's perfectly black body.
Let 'p' and 'E' denote the linear momentum and energy of emitted photon respectively. If the wavelength of incident radiation is increased ___ .
(a) both p and E increase
(b) p increases and E decreases
(c) p decreases and E increases
(d) both p and E decrease.
Show graphical representation of energy distribution spectrum of perfectly black body.
When electron in hydrogen atom jumps from second orbit to first orbit, the wavelength of radiation emitted is λ. When electron jumps from third orbit to first orbit, the wavelength of emitted radiation would be _______.
(A)`27/32lambda`
(B)`32/27lambda`
(C)`2/3lambda`
(D)`3/2lambda`
Find the wavelength at which a black body radiates maximum energy, if its temperature is 427°C.
(Wein’s constant b = 2.898 × 10-3 mK)
(A) 0.0414 × 10-6m
(B) 4.14 × 10-6m
(C) 41.4 × 10-6m
(D) 414 × 10-6m
Explain black body radiation spectrum in terms of wavelength
What is perfectly black body ? Explain Ferry’s black body.
The heat current is written as `(ΔQ)/(Δt)`. Why don't we write `(dQ)/dt?`
Does a body at 20°C radiate in a room, where the room temperature is 30°C? If yes, why does its temperature not fall further?
The thermal radiation emitted by a body is proportional to Tn where T is its absolute temperature. The value of n is exactly 4 for
A blackbody does not
(a) emit radiation
(b) absorb radiation
(c) reflect radiation
(d) refract radiation
The normal body-temperature of a person is 97°F. Calculate the rate at which heat is flowing out of his body through the clothes assuming the following values. Room temperature = 47°F, surface of the body under clothes = 1.6 m2, conductivity of the cloth = 0.04 J s−1 m−1°C−1, thickness of the cloth = 0.5 cm.
A cubical block of mass 1.0 kg and edge 5.0 cm is heated to 227°C. It is kept in an evacuated chamber maintained at 27°C. Assuming that the block emits radiation like a blackbody, find the rate at which the temperature of the block will decrease. Specific heat capacity of the material of the block is 400 J Kg-1 K-1.
A copper sphere is suspended in an evacuated chamber maintained at 300 K. The sphere is maintained at a constant temperature of 500 K by heating it electrically. A total of 210 W of electric power is needed to do it. When the surface of the copper sphere is completely blackened, 700 W is needed to maintain the same temperature of the sphere. Calculate the emissivity of copper.
A body cools down from 50°C to 45°C in 5 mintues and to 40°C in another 8 minutes. Find the temperature of the surrounding.
A metal ball of mass 1 kg is heated by means of a 20 W heater in a room at 20°C. The temperature of the ball becomes steady at 50°C. (a) Find the rate of loss of heat to the surrounding when the ball is at 50°C. (b) Assuming Newton's law of cooling, calculate the rate of loss of heat to the surrounding when the ball rises 30°C. (c) Assume that the temperature of the ball rises uniformly from 20°C to 30°C in 5 minutes. Find the total loss of heat to the surrounding during this period. (d) Calculate the specific heat capacity of the metal.
Which of the following is an example of an ideal black body?
Which of the following series of transitions in the spectrum of hydrogen atom falls in visible region?
