Tag: application of various thermometric scales

Questions Related to application of various thermometric scales

A new temperature scale uses X as a unit of temperature, where the numerical value of the temperature t$ _x$ in this scale is related to the absolute temperature T by t$ _x$ = 3T + 300. If the specific heat of a material using this unit is 1400 J kg$^{-1}$ X${^-1}$ its specificne in the S.I. system of units is

  1. 4200 J kg$^{-1}$ K$^{-1}$

  2. 1400 J kg$^{-1}$ K$^{-1}$

  3. 466.7 J kg$^{-1}$ K$^{-1}$

  4. impossible to determine from the information provided


Correct Option: A
Explanation:

$t _x = 3 T + 300                 Q = ms \Delta 0$
$\Delta t _x = 3 \Delta T$
$\displaystyle S = \frac{Q}{m \Delta \theta}                 S = \frac{Q}{m \Delta \theta}$
Since, unit of 8 is joule in both system
            X                                    T
$m = m _0 kg$                   $m _0 kg$
$Q = Q _0 J$                       $Q _0  J$
$\Delta t _x$                               $\Delta T$
$S _x = \displaystyle \frac{Q _0}{m _0 \Delta t _x} = 1400     S _r = \frac{Q _0}{m _0 \Delta T} = \frac{3 Q}{m _0 \Delta t _x}$
$S _r = 3 \times 1400 = 4200 J-kg^{-1} K^{-1}$

Two glass tumblers have been stuck together (one into the other). They can be seperated by

  1. Placing hot water in the inner tumbler

  2. Placing the tumblers in cold water

  3. Placing the outer tumbler in hot water

  4. Hamming them vigorously


Correct Option: C
Explanation:

The correct answer is option(C).

They can be separated by placing cold water in inside tumbler and placing the outer tumbler in hot water. This way it creates a temperature difference and the glass tumblers get separated easily.

Iron glows in red colour when it is heated to very high temperature. The reason for this is :

  1. Heat we supply consumes red colour at high temperature

  2. Mechanical energy is being converted into heat energy

  3. All metals glow in red colour when heated

  4. Heat energy is being converted into light energy


Correct Option: D
Explanation:

Iron glows in red colour when it is heated to very high temperature cause heat energy is being converted into light energy.

A container having some gas was kept in a moving train. The temperature of the gas in the container will be

  1. Increases slightly

  2. Remain the same

  3. Decrease

  4.  Infinite


Correct Option: B
Explanation:

The correct answer is option(B).

When we say that the temperature of a gas is the measure of the kinetic energy of the gas molecules, we have to find the velocities of the gas molecules in the centre of mass frame of the gas.
If we chose a different inertial frame then the temperature doesn't increase or decrease. 

Heat causes-

  1. change in temperature

  2. chemical change

  3. biological change

  4. all of these


Correct Option: D
Explanation:

heat is a type of energy transfer in which energy flows from a warmer substance or object to a colder one. It can be defined as the total amount of transferred energy excluding any macroscopic work that was done and any transfer of part of the object itself. Transfer of energy as heat can occur through direct contact, through a barrier that is impermeable to matter (as in conduction), by radiation between separated bodies, by way of an intermediate fluid (as in convective circulation), or by a combination of these. By contrast to work, heat involves the stochastic (random) motion of particles (such as atoms or molecules) that is equally distributed among all degrees of freedom, while work is confined to one or more specific degrees of freedom such as those of the center of mass.

Heat causes change in temperature,chemical change,biological change.

A wooden spoon is dipped in a cup of ice cream. It's another end

  1. Become cold by the process of conduction

  2. Become cold by the process of convection

  3. Become cold by the process of radiation

  4. Does not become cold


Correct Option: D
Explanation:

 wooden spoon is dipped in a cup of ice cream. It's another end does not become cold as wood is a bad conductor of heat

Heat of conduction flows in the direction of decreasing: 

  1. Temperature

  2. Pressure

  3. Density

  4. None of these


Correct Option: A
Explanation:
Heat of conduction flows in the direction of decreasing Temperature
The objects will exchange thermal energy, until thermal equilibrium is reached, i.e. until their temperatures are equal.  We say that heat flows from the hotter to the cooler object.  Heat is energy on the move.  
Units of heat are units of energy.  The SI unit of energy is Joule.  Other often encountered units of energy are 1 Cal = 1 kcal = 4186 J, 1 cal = 4.186 J, 1 Btu = 1054 J.

An iron ball at $40^oC$ is dropped in a mug containing water at $40^o$C.

The heat will

  1. flow from iron ball to water

  2. not flow from iron ball to water or from water to iron ball.

  3. flow from water to iron ball.

  4. increase the temperature of both.


Correct Option: B
Explanation:

Thermal Equilibrium - A system is said to be in thermal equilibrium when there is no temperature difference between system and surroundings.

An iron ball at $40^oC$ is dropped in a mug containing water at $40^oC.$

The heat will not flow from iron ball to water or from water to iron ball.

Heat flow can occur due to which of the following situation

  1. Pressure difference

  2. Temperature difference

  3. Density difference

  4. None of these


Correct Option: B
Explanation:

Heat can be transferred from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass. The method used to transfer heat is usually the one that is the most efficient. If there is a temperature difference in a system, heat will always move from higher to lower temperatures.

So, Heat flow occurs due to Temperature Difference

1 Mg of ice at $0^0$C is mixed with 10 Mg of water at $10^0$C. The final temperature is  

  1. $8^0$C

  2. $6^0$C

  3. $4^0$C

  4. $0^0$C


Correct Option: C