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प्रश्न
Estimate the average thermal energy of a helium atom at the temperature of 10 million Kelvin (the typical core temperature in the case of a star).
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उत्तर
At temperature, T = 107 K
Average thermal energy `= 3/2` kT
`= 3/2 xx 1.38 xx 10^(-23) xx 10^7`
= 2.07 × 10–16 J
Hence, the average thermal energy of a helium atom at the core of a star is 2.07 × 10–16 J.
संबंधित प्रश्न
The figure shows the plot of PV/T versus Pfor 1.00×10–3 kg of oxygen gas at two different temperatures.
(a) What does the dotted plot signify?
(b) Which is true: T1 > T2 or T1 < T2?
(c) What is the value of PV/T where the curves meet on the y-axis?
(d) If we obtained similar plots for 1.00 ×10–3 kg of hydrogen, would we get the same value of PV/T at the point where the curves meet on the y-axis? If not, what mass of hydrogen yields the same value of PV/T (for low pressure high temperature region of the plot)? (Molecular mass of H2 = 2.02 u, of O2 = 32.0 u, R = 8.31 J mo1–1 K–1.)
Oxygen is filled in a closed metal jar of volume 1.0 × 10−3 m3 at a pressure of 1.5 × 105Pa and temperature 400 K. The jar has a small leak in it. The atmospheric pressure is 1.0 × 105 Pa and the atmospheric temperature is 300 K. Find the mass of the gas that leaks out by the time the pressure and the temperature inside the jar equalise with the surrounding.
50 m3 of saturated vapour is cooled down from 30°C to 20°C. Find the mass of the water condensed. The absolute humidity of saturated water vapour is 30 g m−3 at 30°C and 16 g m−3 at 20°C.
What do you understand by gas?
Give reasons for the following:
Gas fills the vessel completely in which it is kept.
Match the following:
|
|
Column A |
Column B |
|
(a) |
cm3 |
(i) Pressure |
|
(b) |
Kelvin |
(ii) Temperature |
|
(c) |
Torr |
(iii) Volume |
|
(d) |
Boyle's law |
(iv) `"V"/"T" = ("V"_1)/("T"_1)` |
|
(a) |
Charles's law |
(v) `"PV"/"T" = ("P"_1 "V"_1)/"T"_1` |
|
|
|
(vi) PV = P1V1 |
Fill in the blanks:
If the temperature is reduced to half, ………….. would also reduce to half.
A gas occupies 500 cm3 at a normal temperature. At what temperature will the volume of the gas be reduced by 20% of its original volume, the pressure is constant?
Give reason for the following:
Temperature remaining constant the product of the vol. & the press, of a given mass of dry gas is a constant.
Give reason for the following:
Volumes of gases are converted into s.t.p. conditions and then compared.
If the absolute temperature of a body is doubled, the power radiated will increase by a factor of ______
Show that for monoatomic gas the ratio of the two specific heats is 5:3.
Show that for diatomic gas the ratio of the two specific heats is 7:5.
Estimate the average thermal energy of a helium atom at room temperature (27 °C).
A box of 1.00 m3 is filled with nitrogen at 1.50 atm at 300K. The box has a hole of an area 0.010 mm2. How much time is required for the pressure to reduce by 0.10 atm, if the pressure outside is 1 atm.
Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will ______.
At room temperature, a diatomic gas is found to have an r.m.s. speed of 1930 ms-1. The gas is ______.
P ∝ T at constant volume is the statement of ______.
