Tag: introduction to heat

Questions Related to introduction to heat

During burning of a candle, different zones of combustion in the flame are listed below:

A. outermost zone
B. innermost zone
C. middle zone
The correct order of temperature of zones is :

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

  1. $A > B > C$

  2. $C > B > A$

  3. $B > C > A$

  4. $A > C > B$

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Correct Option: D
Explanation:

The correct order of temperature of zones of candle flames is -
Outermost zone > Middle zone > innermost zone.
Because outerzone will have the highest temperature and inner zone will have the least temperature.

At what temperature is the Fahrenheit scale reading equal to twice of Celsius ?

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

  1. $ 40^0C $

  2. $ 160^0C $

  3. $ 80^0C $

  4. $ 100^0C $

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Correct Option: B
Explanation:

We know the relation between Fahrenheit scale and degree celsius,


$\dfrac{C-0}{100}=\dfrac{F-32}{180}$

Given,

$F=2C$

Then,

$\dfrac{C}{100}=\dfrac{2C-32}{180}$

$\dfrac{C}{100}=\dfrac{C-16}{90}$

$\implies 9C=10C-160$

$\implies C=160^0C$

A man wishes to fit an aluminium ring on steel rod of 1 cm diameter and found it is 0.01 cm smaller in diameter. How much should the on temperature be raised before it just slips on the
$(\alpha _A = 25 \times 10^{-6}/^oC;$ $10 \times 10^{-6}/^oC)$

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

  1. $40^oC$

  2. $50^oC$

  3. $25^oC$

  4. $60^oC$

Show answer
Correct Option: A
Explanation:

${l _2} = {l _1}\left( {1 + {\alpha _A}\Delta T} \right)$

${l _2} = {l _1} + {l _1}{\alpha _A}\Delta T$

$\displaystyle {{{l _2} - {l _1}} \over {{l _1}}} = {\alpha _A}\Delta T$

$\displaystyle {{0.01 \times {{10}^{ - 2}}} \over {1 \times {{10}^{ - 2}} \times 25 \times {{10}^{ - 6}}}} = \Delta T$

$\Delta T = {40^0}C$

Which of the following physical quantities is measured in calories ? 

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

  1. Heat energy

  2. Force

  3. Momentum

  4. Temperature

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Correct Option: A
Explanation:

1 calorie: The amount of energy required to warm $1\ g$ of air-free water from $14.5^oC\ to\ 15.5^oC$ at a constant pressure of $101.325\ kPa$ $(1 atm)$

Name the S.I. unit of heat.

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

  1. Joule

  2. Kelvin

  3. Degree centigrade

  4. All of the above

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Correct Option: A
Explanation:

Answer is (A).

It has the same unit as of energy that's Joule.

State the S.I. unit of heat capacity.

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

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

  2. $ JK^{-2}$

  3. $ JK$

  4. $ JK^{-1}$

Show answer
Correct Option: D
Explanation:

The S.T. unit of heat capacity is heat required per degree rise in temperature. So it is $JK^{-1}$

1 cal = _________

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

  1. 10 joules

  2. 4.18 joules

  3. 4.18 dynes

  4. None of these

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Correct Option: B
Explanation:

1 cal = 4.18 joules

C.G.S unit of heat is calorie.
S.I. unit of heat is joule.

The SI unit of heat is:

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

  1. calorie

  2. joule

  3. dyne

  4. newton

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Correct Option: B

Therm is a unit of

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

  1. heat

  2. temperature

  3. thermometry

  4. mass

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Correct Option: A
Explanation:

The therm (symbol, thm) is a non-SI unit of heat energy equal to100000 British thermal units (Btu). It is approximately the energy equivalent of burning 100 cubic feet (2.83 cubic metres) – often referred to as 1 CCF – of natural gas.

For a gm molecule of an ideal gas

physics measurement and effects of heat sources of heat introduction to heat measuring temperature

  1. ${PV}/{T} = 2$ calories

  2. ${PV}/{T} = 4.2$ calories

  3. ${PV}/{T} = 4.31$ calories

  4. ${PV}/{T} = 4.2 \times {10}^{7}$ ergs

Show answer
Correct Option: B