Molecular Physics | Thermodynamics Answers

Determine the size of spherical balloon required to lift a payload of 1360 kg. The gas to be used is Helium at

101.3 Kpa and 23 0 C. The surrounding air is 101.3 KPa and 10 0 C.

A hot filament radiates 1.50 W of light. The filament has a surface area of 0.250 mm2

and an emissivity of 0.950. what is the temperature (in kelvin) of the filament?

Q5. A 5 kg of ice cube at -10°C is mixed with 0.1 kg of water at 80 °C. There is no heat

loss to the surrounding. The specific heat capacity of ice is 2.22 kJK-1kg ? The specific

heat capacity of water is 4.187 kJK-kg“The specific latent heat of fusion of ice is

333 kJ kg-1

(a) What is the final physical state of the mixture? (Gas, Liquid or Solid?)

Justify your answer using suitable calculations

(b) What is the final temperature of the mixture?

Q 2. A mercury-glass thermometer consists of a glass bulb filled with mercury and a

narrow glass tube attached to the glass bulb. At 0°C, the bulb is completely filled with the

mercury and its radius is 5 mm. As the temperature increases the mercury column rise

through the narrow glass tube whose diameter is 0.3 mm.

What should be the minimum length of the glass tube so that this thermometer can be

used to measure the temperatures up to 100 °C ?

(Hint: ignore the thermal expansion of the glass tube)

liner expansion coefficient of glass = 3.2 x 10-6 °C-1

volume expansion coefficient of mercury = 1.82 x 10°C

Work is done by a substance in reversible non-flow manner in accordance with

𝑉 = 100 𝑓𝑡3 where P is in psia. Evaluate the work done on or by the substance as the

𝑃

pressure increases from 10 psia to 100 psia

If 100ft of atmospheric air at zero Fahrenheit temperature are compressed to a volume of 1ft at a temperature of 200F. what will be the pressure of the air in psi? Ans. 2109 psia (EE board problem)

An automobile tire is inflated to 32 psig pressure at 50 F. After being driven the temperature rise to 75F. Determine the final gage pressure assuming the volume remains constant.

Air is compressed in a diesel engine from an initial pressure of 13 psia and a temperature of 120 F to one-twelfth of its original volume. Calculate the final temperature assuming the compression is adiabatic

an isentropic compression process, air is compressed to an initial pressure of 100 psi to 200 psi. What is the final volume in cubic inches if the initial volume is 10 in^3?

The standard deviation is the square root of the variance, which, in turn, is related to the first and second moments by:

var = <x²> - <x>²

Find the variance and the standard deviation of the normal distribution.