Advertisements
Advertisements
प्रश्न
Find the temperature of a blackbody if its spectrum has a peak at (a) λmax = 700 nm (visible), (b) λmax = 3 cm (microwave region) (c) λmax = 3 m (short radio waves). (Take Wien’s constant b = 2.897 × 10-3 m.K).
Advertisements
उत्तर
Given: (a) λmax = 700 nm = 700 × 10-9 m,
(b) λmax = 3 cm = 3 × 10-2 m,
(c) λmax = 3 cm,
b = 2.897 × 10-3 m.K.
∴ λmax T = b
(a) T = `"b"/lambda_"max"`
`= (2.897 xx 10^-3 "m"."K")/(700 xx 10^-9 "m")`
`= (2.897 xx 10^-3)/(7 xx 10^-7)`
= 0.4138 × 104
= 4138 K
(b) T = `"b"/lambda_"max"`
`= (2.897 xx 10^-3 "m"."K")/(3 xx 10^-2 "m")`
`= (2.879 xx 10^-1 "K")/3`
= 0.966 × 10-1 K
= 0.0966 K
(c) T = `"b"/lambda_"max"`
`= (2.897 xx 10^-3 "m.K")/(3 " m")`
= 0.966 × 10-3 K
APPEARS IN
संबंधित प्रश्न
If the molecules were not allowed to collide among themselves, would you expect more evaporation or less evaporation?
Is it possible to boil water at room temperature, say 30°C? If we touch a flask containing water boiling at this temperature, will it be hot?
When you come out of a river after a dip, you feel cold. Explain.
The pressure of an ideal gas is written as \[P = \frac{2E}{3V}\] . Here E refers to
The mean square speed of the molecules of a gas at absolute temperature T is proportional to
Air is pumped into the tubes of a cycle rickshaw at a pressure of 2 atm. The volume of each tube at this pressure is 0.002 m3. One of the tubes gets punctured and the volume of the tube reduces to 0.0005 m3. How many moles of air have leaked out? Assume that the temperature remains constant at 300 K and that the air behaves as an ideal gas.
Use R = 8.3 J K-1 mol-1
Figure shows two vessels A and B with rigid walls containing ideal gases. The pressure, temperature and the volume are pA, TA, V in the vessel A and pB, TB, V in the vessel B. The vessels are now connected through a small tube. Show that the pressure p and the temperature T satisfy `Ρ/T = 1/2 ({P_A}/{T_A}+{P_B}/{T_B))` when equilibrium is achieved.
The weather report reads, "Temperature 20°C : Relative humidity 100%". What is the dew point?
The temperature and the dew point in an open room are 20°C and 10°C. If the room temperature drops to 15°C, what will be the new dew point?
Answer in brief:
A gas in a cylinder is at pressure P. If the masses of all the molecules are made one-third of their original value and their speeds are doubled, then find the resultant pressure.
Answer in brief:
Compare the rms speed of hydrogen molecules at 127°C with rms speed of oxygen molecules at 27ºC given that molecular masses of hydrogen and oxygen are 2 and 32 respectively.
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.
When a gas is heated, its temperature increases. Explain this phenomenon on the basis of the kinetic theory of gases.
Energy is emitted from a hole in an electric furnace at the rate of 20 W when the temperature of the furnace is 727°C. What is the area of the hole? (Take Stefan’s constant σ to be 5.7 × 10-8 Js-1 m-2K-4.)
The number of degrees of freedom, for the vibrational motion of a polyatomic molecule, depends on the ______
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?
A metal cube of length 4 cm radiates heat at the rate of 10 J/s. Find its emissive power at a given temperature.
The graph of kinetic energy against the frequency v of incident light is as shown in the figure. The slope of the graph and intercept on X-axis respectively are ______.
A ring of mass m and radius r rotates about an axis passing through its centre and perpendicular to its plane with angular velocity `omega`. Its kinetic energy is ______.
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) ____________.
An ideal gas in a container of volume 500 cc is at a pressure of 2 × 105 N/m2. The average kinetic energy of each molecule is 6 × 10−21 J. The number of gas molecules in the container is ______.
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 ______.
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.
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.
A proton, a deuteron and an α-particle with same kinetic energy enter into a uniform magnetic field at right angle to magnetic field. The ratio of the radii of their respective circular paths is ______.
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 ______.
If a = 0. 72 and t = 0.04, then the value of r is ______.
Which of the following materials is diathermanous?
