Tag: heat - measurement

Questions Related to heat - measurement

Which of the following is not true about Laboratory thermometers ?

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. Laboratory thermometers are used to measure temperatures with a high degree of precision.

  2. Laboratory thermometers are used to measure body temperature.

  3. Range of laboratory thermometer is -10C to 110C

  4. Laboratory thermometers are designed for lab purposes such as checking boiling point, freezing point etc.

Show answer
Correct Option: B
Explanation:

A laboratory thermometer is a tool used in laboratories to measure temperature with high accuracy. It can be partially or fully immersed in the substance being measured. A laboratory thermometer is recognizable by its long stem with a silver bulb at the end. The silver color in the bulb normally indicates the presence of mercury. Mercury expands as the temperature increases, thus raising the reading, while decreasing temperatures contract the mercury, lowering the reading. Mercury-in-glass thermometers are less used in the 21st century as preference is shifted to other types of thermometers, such as digital, alcohol-filled and organic-based thermometers.

hence,Laboratory thermometers are $not$ used to measure body temperature.

Which of the following is the range of temperature recorded by a laboratory thermometer ?

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. $0^oC$ to $100^oC$

  2. $-10^oC$ to $110^oC$

  3. $30^oC$ to $120^oC$

  4. $45^oC$ to $145^oC$

Show answer
Correct Option: B
Explanation:

A laboratory thermometer is used for measuring temperatures other than the human body temperature. It ranges from -10˚C to 110˚C. Laboratory thermometers are designed for lab purposes such as checking boiling point, freezing point, or temperature of other substances

Choose the correct answer from the alternatives given :
For measuring very high temperature, we use

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. Mercury thermometer

  2. Thermoelectric pyrometer

  3. Platinum resistance thermometer

  4. None of the above

Show answer
Correct Option: B
Explanation:

Thermoelectric pyrometer is an instrument which uses one or more thermocouples to measure high temperature . 

Hence, option B is correct.

If a thermometer reads freezing point of water as $20^{\circ}C$ and boiling point at $150^{\circ}C$ how much thermometer read when the actual temperature is $60^{\circ}C$.

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. $98^{\circ}C$

  2. $110^{\circ}C$

  3. $40^{\circ}C$

  4. $60^{\circ}C$

Show answer
Correct Option: A
Explanation:
We let the unknown degree scale be called ${x}^{\circ}$
Now we know that the freezing point$={20}^{\circ}x$
The boiling point$={150}^{\circ}x$
This also means that ${20}^{\circ}x= {0}^{\circ}$ C($\because$ on a Celcius Scale, the freezing point is ${0}^{\circ}$)
And ${150}^{\circ}x={100}^{\circ}$C (On a  Celcius Scale, boiling point is ${100}^{\circ}$)
Also ${(150-20)}^{\circ}x= {100}^{\circ}$C ($\because$ on a Celcius Scale ${100}^{\circ}-{0}^{\circ}={100}^{\circ}$)
So, if ${100}^{\circ}$C$={130}^{\circ}x$
Then ${1}^{\circ}$C$={1.3}^{\circ}x$
To go from $C$ degree  to $x$, we need to use:
$x=1.3C+20$  
And $C=\dfrac{(x-20)}{1.3}$
So if the temperature given is ${60}^{\circ}$C, then we calculate $x$ as:
$C=\dfrac{(x-20)}{1.3}$  
$\Rightarrow 60=\dfrac{(X-20)}{1.3}$  
$\Rightarrow 60\times 1.3=x-20$  
$\Rightarrow 78=x-20$  
$\Rightarrow x= {98}^{\circ}$  
So ${60}^{\circ}$C will be equal to ${98}^{\circ}$ 

Find the correct temperature if the thermometer reads $20^o$C?

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. $20^o$C

  2. $12.5^o$C

  3. $25^o$C

  4. $30^o$C

Show answer
Correct Option: B

Faulty thermo has its fixed pts marked 5g. what is correct temperature in celcius when it reads 5g?

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. $ 45^0 $

  2. $ 60^0 $

  3. $ 75^0 $

  4. none

Show answer
Correct Option: A

The freezing point on a thermometer is marked as  $ 20^o$ and the boiling point as $150^o$. A temperature of $(60^o C)$on this thermometer will be read as:

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. $40^o$

  2. $65^o$

  3. $98^o$

  4. None of these

Show answer
Correct Option: C
Explanation:

$\begin{array}{l} By\, \, u\sin  g\, the\, \, formula \ \dfrac { { { T _{ t } }-{ T _{ fP } } } }{ { { T _{ BP } }-{ T _{ fp } } } } =\dfrac { { T-0 } }{ { 100-0 } }  \ \dfrac { { { T _{ t } }-20 } }{ { 150-20 } } =\dfrac { { 60 } }{ { 100 } }  \ { T _{ t } }-20=\dfrac { { 60\times 130 } }{ { 100 } }  \ { T _{ t } }=78+20 \ ={ 98^{ \circ  } } \ Hence,\, the\, option\, C\, \, is\, the\, correct\, answer. \end{array}\ $

Two thermometers, one calibrated in celsius and the other in fahrenheit scale, are used to measure the temperature of the same object. if the readings are in $ ^0C $ and $ ^0F $ then :

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. C>F

  2. F

  3. F=C

  4. $ F \gtreqless C $

Show answer
Correct Option: C

At low temperatures ................. type of thermometer is used.

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. mercury thermometer

  2. water thermometer

  3. alcohol thermometer

  4. thermometers cannot be used

Show answer
Correct Option: C
Explanation:

Alcohol thermometer.
Alcohol expands uniformly.

It has a low freezing point (-115 degree centigrade) therefore it is very suitable for the place where the temperature gets very low.
It is an easily available cheap liquid, which is safe to use.
Alcohol is cheaper than mercury, and if you break the thermometer, it is not toxic.

The boiling point of mercury is 367$^o$C. A mercury thermometer can be used to measure a temperature of 500$^o$C;

physics heat - measurement thermometers application of various thermometric scales different types of thermometers

  1. by filling the space above mercury with oxygen at high pressure

  2. by filling the space above mercury with nitrogen at low pressure

  3. by filling the space above mercury with nitrogen at high pressure

  4. by keeping the space above mercury as vacuum

Show answer
Correct Option: C
Explanation:

The mercury thermometer can be used above its boiling point by filling up the space above mercury with nitrogen at high pressure because as pressure increases, boiling point also increases.