Heat RT Physics

If K is the Boltzmann constant, the average KE of a gas molecule at absolute temperature T is
 

•  $KT/2$  

•  $3KT/4$  

•  $KT$  

•  $3KT/2$  

If the temperature of a patient is 40^oC, his temperature on the Fahrenheit scale will be

• 72^oC

• 96^oF

• 100^oF

• 104^oF

By which of the following methods could a cup of hot tea lose heat, if situated on metal table in a class room

• Conduction

• Convection

• Radiation and evaporation

• All of these

The root mean square speed of molecules of a gas at absolute temperature T is proportional to

• 1/T

• T

• $T^2$

• $√T$

The temperature of an ideal gas is decreased from 120 K to 30 K. If at 120 K the root mean square velocity of the gas molecules is V, at 30 K it becomes

• 4V

• 2V

• v/4

• V/2

The root mean square speed of gas molecules

• Is the same for all gases at the same temperature

• Depends on the mass of the gas molecules and its temperature

• Is independent of the density and pressure of the gas

• Depends only on the temperature and volume of the gas.

It is hotter at the same distance over the top of a fire than it is on the side of it mainly because

• Heat is radiated upwards

• Air conducts heat upward

• Convection takes more heat upward

• Conduction, convection and radiation all contribute significantly in transferring heat upward.

Device used to measure very high temperature is

• Pyrometer

• Thermometer

• Barometer

• Calorimeter

The following four gases are at the same temperature. In which gas do the molecules have maximum root mean square speed?

• Nitrogen

• Oxygen

• Hydrogen

• Carbon dioxide

The speediest mode of heat transfer is

• Conduction

• Convection

• Radiation

• Combustion