Advertisements
Advertisements
प्रश्न
Compare the rate of radiation of metal bodies at 727 °C and 227 °C.
Advertisements
उत्तर
Given:
T1 = 727 °C = 727 + 273 = 1000 K,
T2 = 227 °C = 227 + 273 = 500 K
To find: Ratio of radiation `[((dQ)/dt)_1/((dQ)/dt)_2]`
Formula:
`(dQ)/dt = σAeT^4`
Calculation:
From formula,
`((dQ)/dt)_1 = σAeT_1^4` ...............(1)
`((dQ)/dt)_2 = σAeT_2^4` ...............(2)
Dividing equation (1) by (2),
`((dQ)/dt)_1/((dQ)/dt)_2 = (σAeT_1^4)/(σAeT_2^4) = (T_1/T_2)^4`
= `(1000)^4/(500)^4 = 16`
The rate of radiation of the metal sphere at 727 °C and 227 °C is 16:1.
APPEARS IN
संबंधित प्रश्न
Can we define the temperature of (a) vacuum, (b) a single molecule?
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?
Which of the following parameters is the same for molecules of all gases at a given temperature?
The mean square speed of the molecules of a gas at absolute temperature T is proportional to
The process on an ideal gas, shown in figure, is
Find the number of molecules of an ideal gas in a volume of 1.000 cm3 at STP.
The temperature and pressure at Simla are 15.0°C and 72.0 cm of mercury and at Kalka these are 35.0°C and 76.0 cm of mercury. Find the ratio of air density at Kalka to the air density at Simla.
Use R=8.314J K-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
An ideal gas is trapped between a mercury column and the closed-end of a narrow vertical tube of uniform base containing the column. The upper end of the tube is open to the atmosphere. The atmospheric pressure equals 76 cm of mercury. The lengths of the mercury column and the trapped air column are 20 cm and 43 cm respectively. What will be the length of the air column when the tube is tilted slowly in a vertical plane through an angle of 60°? Assume the temperature to remain constant.
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.
Figure shows two rigid vessels A and B, each of volume 200 cm3, containing an ideal gas (Cv = 12.5 J K−1 mol−1). The vessels are connected to a manometer tube containing mercury. The pressure in both the vessels is 75 cm of mercury and the temperature is 300 K. (a) Find the number of moles of the gas in each vessel. (b) 5.0 J of heat is supplied to the gas in vessel A and 10 J to the gas in vessel B. Assuming there's no appreciable transfer of heat from A to B, calculate the difference in the heights of mercury in the two sides of the manometer. Gas constant, R = 8.3 J K−1 mol−1.
Using figure, find the boiling point of methyl alcohol at 1 atm (760 mm of mercury) and at 0.5 atm.
If the density of oxygen is 1.44 kg/m3 at a pressure of 105 N/m2, find the root mean square velocity of oxygen molecules.
Explain, on the basis of the kinetic theory of gases, how the pressure of a gas changes if its volume is reduced at a constant temperature.
Find the kinetic energy of 5000 cc of a gas at STP, given the standard pressure is 1.013 × 105 N/m2.
Calculate the average molecular kinetic energy
- per kmol
- per kg
- per molecule
of oxygen at 127°C, given that the molecular weight of oxygen is 32, R is 8.31 J mol−1K−1 and Avogadro’s number NA is 6.02 × 1023 molecules mol−1.
The emissive power of a sphere of area 0.02 m2 is 0.5 kcal s-1m-2. What is the amount of heat radiated by the spherical surface in 20 seconds?
The number of degrees of freedom, for the vibrational motion of a polyatomic molecule, depends on the ______
Calculate the value of λmax for radiation from a body having a surface temperature of 3000 K. (b = 2.897 x 10-3 m K)
Calculate the energy radiated in one minute by a blackbody of surface area 200 cm2 at 127 °C (σ = 5.7 x 10-8 J m-2 s-1 K-4)
Why the temperature of all bodies remains constant at room temperature?
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?
Two molecules of a gas have speeds of 9 × 10 6 ms−1 and 1 × 106 ms−1, respectively. What is the root mean square speed of these molecules?
A gas mixture consists of molecules of types A, B and C with masses mA > mB > mC. Rank the three types of molecules in decreasing order of rms speeds.
For a particle moving in vertical circle, the total energy at different positions along the path ______.
According to the kinetic theory of gases, at a given temperature, molecules of all gases have the same ______.
