Tag: heat - measurement

Questions Related to heat - measurement

We cannot use mercury thermometer at low temperatures because:

physics heat - measurement application of various thermometric scales different types of thermometers measuring temperature introduction to temperature

  1. Glass might break down at low temperature.

  2. Heat does not flow from the body whose measurement we are taking with the thermometer.

  3. At low temperatures mercury becomes transparent and it becomes difficult to take the readings.

  4. Mercury freezes at low temperatures.

Show answer
Correct Option: D
Explanation:

Mercury, which is used as a thermometric liquid, has the following characteristic properties:

1. Mercury has a high boiling point of about $357^{\circ}$C and therefore can be used to measure temperatures as high as $357^{\circ}$C.

2. Mercury has a freezing point of about $-39^{\circ}$C and hence it is suitable in thermometers to record low temperatures (although not very low temperatures).

3. Mercury is opaque and has a shining silvery colour of its own, making it clearly visible in the capillary tube of a thermometer. 


4. Mercury needs very little heat to expand and so it can easily measure the temperature of a body without causing a decrease in the body's temperature.

5. Mercury does not stick to the side of the glass capillary tube of a thermometer. Therefore, it allows accurate temperature measurement.

6. Mercury is a good conductor of heat.

7. Mercury is relatively expensive.

Mercury is commonly used as a thermometric fluid rather than water because

physics heat - measurement application of various thermometric scales different types of thermometers measuring temperature introduction to temperature

  1. specific heat of mercury is less than water

  2. specific heat of mercury is more than water

  3. mercury has greater visibility than water

  4. density of mercury is more than the water

Show answer
Correct Option: C
Explanation:
Mercury is commonly used as a thermometric fluid rather than water because mercury has greater visibility than water
Mercury has high melting and boiling points making it a liquid over a broad range of temperature.
Since it is a metal, it has a stable coefficient of expansion hence it expands uniformly and noticeably for a slight change of temperature.
Mercury is a non sticky viscous metal and hence it makes a clear meniscus, helpful in readings.
Mercury will not expand when it solidifies hence it doesn’t break the glass tube of the thermometer.

Compared to other liquids, why is mercury preferred as a barometric fluid?

physics heat - measurement application of various thermometric scales different types of thermometers measuring temperature introduction to temperature

  1. Height of mercury barometer is smaller so it is more convenient to handle

  2. Mercury does not stick to the glass surface of barometric tube

  3. Mercury shines so it is easier to take the observations

  4. Coefficient of expansion of mercury is less than other liquids

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Correct Option: A,B

A thermometer is gradated in millimeters . It registers -3 mm when the bulb of themometer is a pure melting ice  and 22 mm when the thermometer is in stem at a pressure of 1 atmosphere. The temperature in $^{ \circ  }C$  when the thermometer registers 13 mm is 

physics heat - measurement application of various thermometric scales different types of thermometers measuring temperature introduction to temperature

  1. $\frac { 13 }{ 25 } \times 100$

  2. $\dfrac { 16 }{ 25 } \times 100$

  3. $\dfrac { 13 }{ 22 } \times 100$

  4. $\dfrac { 16 }{ 22 } \times 100$

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Correct Option: A

Heat energy produces a sensation of-

physics heat - measurement sources of heat introduction to heat measuring temperature

  1. warmth

  2. coldness

  3. both warmth and coldness

  4. none of these

Show answer
Correct Option: A
Explanation:
Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases. Heat energy can be transferred from one object to another. The transfer or flow due to the difference in temperature between the two objects is called heat.
Heat energy produces a sensation of warmth

State whether given statement is True or False
A wooden chair feels colder than an iron chair in winter

physics heat - measurement sources of heat introduction to heat measuring temperature

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Metal conducts heat much better than wood does. Since your hand is hotter than room temperature, both the metal and the wood conduct heat away from it.an iron chair in winter feels colder

State whether given statement is True or False :

Mud houses are hot in summer and cold in winter.

physics heat - measurement sources of heat introduction to heat measuring temperature

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Mud houses have thatched roofs. The insulating effect of the thatch prevents heat from getting in very quickly (cool in summer) and heat getting out very quickly (warm in winter). Secondly, mud houses are made up of mud, which has large pores. As evaporation causes cooling, mud houses feel cooler in summer 

This is why mud houses are cool in summer and hot in winter.

Heat will flow from

physics heat - measurement sources of heat introduction to heat measuring temperature

  1. Hot body to cold body

  2. Cold body to hot body

  3. two bodies at the same temperature

  4. None of these

Show answer
Correct Option: A
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.Heat will flow from Hot body to cold body

Beaker A contains hot water. Beaker B contains cold water. Beaker C contains a mixture of hot and cold water. If initially your hand is put into a beaker containing ice, then putting your hand in which of the beakers A, B or C will give a sensation of warmth?  

physics heat - measurement sources of heat introduction to heat measuring temperature

  1. A

  2. B

  3. C

  4. All of the above.

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Correct Option: D

A thermostat is?

physics heat - measurement sources of heat introduction to heat measuring temperature

  1. A device used to maintain a constant temperature of a water bath or an oven

  2. A modern type of thermoflask which work on the principle of equipartition of heat energy

  3. An instrument by which the accuracy of thermometers is determined

  4. A device which varies the temperature of a both

Show answer
Correct Option: A
Explanation:

A thermostat is a device that automatically regulates temperature, or that activates a device when the temperature reaches a certain point.

Thus, it can be used to maintain a constant temperature of a water bath or an oven.
Hence, option A is correct.