Heat questions | form five Physics

A black ball of radius 1 m is maintained at a temperature of 30°​ C ​ . How much heat is radiated by the ball in 4 seconds?

(i) Give a common example of adiabatic process.
(ii) What happens to the internal energy of a gas during adiabatic expansion?

A mass of an ideal gas of volume 400cm​ ³ at 288K expands adiabatically. If its temperature falls to 273K;
(i) Find the new volume of the gas.
(ii) Calculate the final volume of the gas if it is then compressed isothermally until the pressure returns to its original value.

State the following according to heat exchange:
(i) Prevost`s theory.
(ii) Wien`s displacement law.

Briefly explain why;
(i) Steam pipes are wrapped with insulating materials?

(ii) Stainless steel cooking pans fitted with extra copper at the bottom are more preferred?

The value of the property X of a certain substance is given by;
X​ _θ = X​ _σ 0.5θ + 2 × 10​ ^-4​ θ​ ^2​ , Where θ is the temperature in degrees celsius. What would be the celsius temperature defined by the property X which corresponds to a temperature of 50°C on
this gas thermometer scale?

Briefly explain why:
(i) A body with large reflectivity is a poor emitter.
(ii) The earth without its atmosphere would be too cold to live.

Identify two factors on which the coefficient of thermal conductivity of a material depends.

A brass boiler of base area 1.50×10​ ^-1​ m ² ​ and thickness of 1.0​ cm boils water at the rate of 6.0​ kg ​ /min when placed on a gas stove. Estimate the temperature of the part of the flame in
contact with the boiler.

Briefly describe the working principle of a thermocouple.