Advertisements
Advertisements
प्रश्न
A solid at temperature T1 is kept in an evacuated chamber at temperature T2 > T1. The rate of increase of temperature of the body is proportional to
विकल्प
`T_2 - T_1`
`T^2 - T^2`
`T_2^3 - T_1^3`
`T_2^4 - T_1^4`
Advertisements
उत्तर
`T_2^4 - T_1^4`
From Stefan-Boltzmann law, the energy of thermal radiation emitted per unit time by a blackbody of surface area A is given by `u = σAT^4`
Here, `σσ` is Stefan-Boltzmann constant.
Since the temperature of the solid is less than the surroundings, the temperature of the solid will increase with time until it reaches equilibrium with the surroundings. The rate of emission from the solid will be proportional to `T_1^4` and rate of emission from the surroundings will be proportional to `T_2^4`.
So, the net rate of increase in temperature will be proportional to `T_2^4 - T_1^4`.
APPEARS IN
संबंधित प्रश्न
Explain why the earth without its atmosphere would be inhospitably cold
Standing in the sun is more pleasant on a cold winter day than standing in shade. Is the temperature of air in the sun considerably higher than that of the air in shade?
Cloudy nights are warmer than the nights with clean sky. Explain
Why is a white dress more comfortable than a dark dress in summer?
A heated body emits radiation which has maximum intensity near the frequency v0. The emissivity of the material is 0.5. If the absolute temperature of the body is doubled.
(a) the maximum intensity of radiation will be near the frequency 2v0
(b) the maximum intensity of radiation will be near the frequency v0/2
(c) the total energy emitted will increase by a factor of 16
(d) the total energy emitted will increase by a factor of 8
A solid sphere and a hollow sphere of the same material and of equal radii are heated to the same temperature.
(a) Both will emit equal amount of radiation per unit time in the biginning
(b) Both will absorb equal amount of radiation from the surrounding in the biginning.
(c) The initial rate of cooling (dT/dt) will be the same for the two spheres
(d) The two spheres will have equal temperature at any instant
Wein's constant is 2892 × 10-6 SI unit and the value of λm for moon is 14.46 micron. The surface temperature of moon is ______.
You place your hands near a burning candle and feel warmth on both sides of the flame. What does this observation mainly show?
Which statement best describes thermal radiation from everyday objects like trees, roads, and buildings at night?
Two identical metal tins with water are kept in sunlight. One is black and the other shiny. Why does water in the black tin become hotter?
Why are cooking utensils like pans made of metal but fitted with plastic or wooden handles?
A perfect black body has an emissivity value of ______.
Thermal radiation is described as a two-step process. Which of the following correctly identifies both steps in the correct order?
In the experiment where a test tube of water is heated from the top with ice at the bottom, the ice does not melt. What is the primary reason for this?
Which of the following properties is shared by both thermal radiation and visible light?
