Advertisements
Advertisements
प्रश्न
If a = 0.72 and r = 0.24, then the value of tr is ______.
विकल्प
0.02
0.04
0.4
0.2
Advertisements
उत्तर
If a = 0.72 and r = 0.24, then the value of tr is 0.04.
Explanation:
Express the relation of absorptivity. The fraction of light/ray/radiation absorbed by a surface is called absorptivity.
`a = (G_(abs))/G`
`G_(abs) =Ga`
Here, `G_(abs)` is absorbed radiation and G is incident radiation.
Express the relation of reflectivity.
The fraction of light reflected by a surface is known as reflectivity.
`r = (G_(ref))/G`
`G_(ref) = Gr`
Here, `G_(ref)` is reflected radiation.
Express the relation of transmissivity. The fraction of light/ray/radiation transmitted by a surface is known as transmissivity.
`t_r = G_t/G`
`G_t = Gt_r`
Here, `G_t` is transmitted radiation.
Express the relation of 1st law of thermodynamics. Sum of all radiation (absorbed, reflected and transmitted) should be equals to the total radiation.
`G_(abs) + G_(ref) + G_t = G` ......(i)
Substitute `Ga` for `G_(abs), G_r` for `G_(mf)` and Gt for Gt in equation (i).
`(Ga)/G + (Gr)/G + (Gt_r)/G` = 1
`a + r + t_r` = 1
Substitute 0.72 for a and 0.24 for r to find transmitted radiation.
0.72 + 0.24 + tr = 1
tr = 1 – 0.96
tr = 0.04
APPEARS IN
संबंधित प्रश्न
When we place a gas cylinder on a van and the van moves, does the kinetic energy of the molecules increase? Does the temperature increase?
Can we define the temperature of (a) vacuum, (b) a single molecule?
Consider a gas of neutrons. Do you expect it to behave much better as an ideal gas as compared to hydrogen gas at the same pressure and temperature?
It is said that the assumptions of kinetic theory are good for gases having low densities. Suppose a container is so evacuated that only one molecule is left in it. Which of the assumptions of kinetic theory will not be valid for such a situation? Can we assign a temperature to this gas?
The pressure of an ideal gas is written as \[P = \frac{2E}{3V}\] . Here E refers to
The mean speed of the molecules of a hydrogen sample equals the mean speed of the molecules of a helium sample. Calculate the ratio of the temperature of the hydrogen sample to the temperature of the helium sample.
Use R = 8.314 JK-1 mol-1
During an experiment, an ideal gas is found to obey an additional law pV2 = constant. The gas is initially at a temperature T and volume V. Find the temperature when it expands to a volume 2V.
Use R = 8.3 J K-1 mol-1
The condition of air in a closed room is described as follows. Temperature = 25°C, relative humidity = 60%, pressure = 104 kPa. If all the water vapour is removed from the room without changing the temperature, what will be the new pressure? The saturation vapour pressure at 25°C − 3.2 kPa.
A glass contains some water at room temperature 20°C. Refrigerated water is added to it slowly. when the temperature of the glass reaches 10°C, small droplets condense on the outer surface. Calculate the relative humidity in the room. The boiling point of water at a pressure of 17.5 mm of mercury is 20°C and at 8.9 mm of mercury it is 10°C.
Answer in brief:
What will happen to the mean square speed of the molecules of a gas if the temperature of the gas increases?
Compare the rates of emission of heat by a blackbody maintained at 727°C and at 227°C, if the black bodies are surrounded by an enclosure (black) at 27°C. What would be the ratio of their rates of loss of heat?
The number of degrees of freedom, for the vibrational motion of a polyatomic molecule, depends on the ______
The power radiated by a perfect blackbody depends only on its ______
On what, the values of absorption coefficient, reflection coefficient, and transmission coefficient depend, in addition to the material of the object on which the radiation is an incident?
Why the temperature of all bodies remains constant at room temperature?
The average translational kinetic energy of gas molecules depends on ____________.
When photons of energy hv fall on a metal plate of work function 'W0', photoelectrons of maximum kinetic energy 'K' are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be ______.
The average translational kinetic energy of a molecule in a gas becomes equal to 0.49 eV at a temperature about (Boltzmann constant = 1.38 x 10-23 JK-1) ____________.
Average kinetic energy of H2 molecule at 300K is 'E'. At the same temperature, average kinetic energy of O2 molecule will be ______.
The average translational kinetic energy of a molecule in a gas is 'E1'. The kinetic energy of the electron (e) accelerated from rest through p.d. 'V' volt is 'E2'. The temperature at which E1 = E2 is possible, is ______.
Volume versus temperature graphs for a given mass of an ideal gas are shown in figure at two different values of constant pressure. What can be inferred about relation between P1 and P2?
An inflated rubber balloon contains one mole of an ideal gas, has a pressure p, volume V and temperature T. If the temperature rises to 1.1 T, and the volume is increased to 1.05 V, the final pressure will be ______.
An insulated container containing monoatomic gas of molar mass m is moving with a velocity vo. If the container is suddenly stopped, find the change in temperature.
23Ne decays to 23Na by negative beta emission. Mass of 23Ne is 22.994465 amu mass of 23Na is 22.989768 amu. The maximum kinetic energy of emitted electrons neglecting the kinetic energy of recoiling product nucleus is ______ MeV.
For a particle moving in vertical circle, the total energy at different positions along the path ______.
When a particle oscillates simple harmonically, its kinetic energy varies periodically. If frequency of the particle is n, then the frequency of the kinetic energy is ______.
At what temperature will therms velocity of a gas be four times its value at STP?
If a = 0. 72 and r = 0.24, then the value of t is ______.
