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Different types of thermometers - class-VII

Description: different types of thermometers
Number of Questions: 20
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Tags: heat - measurement physical quantities and measurement measurements temperature and heat paths of heat flow physics heat
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Two thermometers are constructed in the same way except that one has a spherical bulb and the other a cylindrical bulb; which one will respond quickly to temperature changes?

  1. Spherical bulb thermometer

  2. Cylindrical bulb thermometer

  3. both equally

  4. either


Correct Option: A

At the top of a mountain, a thermometer read ${7}^{0}C$ and barometer reads $70\, cm$ of Hg. At the bottom of the mountain, the barometer reads $76\,cm$ of Hg and thermometer reads ${27}^{0}C$. The density the density at the bottom.

  1. $0.99$

  2. $0.9$

  3. $0.89$

  4. $0.95$


Correct Option: A

A thermometer reads $0^{\circ}$ as $10^{\circ}$ and $100^{\circ}$ as $90^{\circ}C$. Then
Find the reading of the temperature if the temperature is $40^{\circ}C$?

  1. $42^{\circ}C$

  2. $40^{\circ}C$

  3. $35^{\circ}C$

  4. $45^{\circ}C$


Correct Option: A

If two temperatures differ by 25 degrees on Celsius scale, the difference of temperature on Fahrenheit scale is 

  1. $65^{\circ}$

  2. $45^{\circ}$

  3. $38^{\circ}$

  4. $25^{\circ}$


Correct Option: B
Explanation:

Each Celsius degree equals 5/9ths of a Fahrenheit degree. 

Each Fahrenheit degree equals 9/5ths of a Celsius degree. 

A 25 degree difference in Celsius would be 25 x 9/5 = 45 degrees Fahrenheit.

A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered unit the Fahrenheit thermometre registers a temperature of $140^o$. The fall of temperature as registered by the Centigrade thermometre is :

  1. $80^o$C

  2. $40^o$C

  3. $50^o$C

  4. $90^o$C


Correct Option: B

On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are $39^o$W and $239^o$W respectively. What will be the temperature on the new scale, corresponding to a temperature of $39^o$C on the Celsius scale ?

  1. $78^o$W

  2. $117^o$W

  3. $200^o$W

  4. $139^o$W


Correct Option: B

The range of a clinical thermometer is

  1. 0-100$^0$C

  2. 32-214$^0$F

  3. 0-1273$^0$C

  4. 35-42$^0$C


Correct Option: D
Explanation:

A clinical thermometer is used to measure the body temperature which normally remains between $35^{\circ}$C and $42^{\circ}$C.


People boil water as safe measure to drink because:

  1. Boiled water is tasty

  2. Boiled water is more powerful

  3. Heating water is fashionable

  4. Excessive heat kills the microorganisms present in the water


Correct Option: D
Explanation:

People boil water as safe measure to drink because excessive heating kills the microorganisms present in the water and becomes safe to drink it.

At low temperatures ________  type of thermometer is used.

  1. mercury thermometer

  2. water thermometer

  3. alcohol thermometer

  4. thermometers cannot be used


Correct Option: C
Explanation:

Alcohol has a low freezing point.

The most commonly used thermometric substance is

  1. water

  2. alcohol

  3. mercury

  4. steam


Correct Option: C
Explanation:

Mercury is the only one in liquid state at room temperature. It's used in thermometers because it has high coefficient of expansion. Hence, the slightest change in temperature is notable when it's used in a thermometer. It also has a high boiling point which makes it very suitable to measure higher temperatures, and it doesn't stick to glass.

State whether given statement is True or False
The upper standard point of a thermometer is 273 K

  1. True

  2. False


Correct Option: B
Explanation:

The lower fixed point, or ice point, is the temperature of pure melting ice at normal atmospheric pressure. The upper fixed point, or steam point, is the temperature of pure boiling water at normal atmospheric pressure.

A barometer with a brass scale correct at $0^oC$ reads $70\ cm$ of mercury on a day when the air temperature is $40^oC$. the correct reading at $0^oC$ is (Coefficient of real expansion of mercury, is $0.00018/^oC$ and the coefficient of linear expansion of brass is $0.000018/^oC$.

  1. $60.5\ cm$

  2. $69.5\ cm$

  3. $20.5\ cm$

  4. $50.00\ cm$


Correct Option: B
Explanation:

If the correct heading of barometer at $0^oC$ is $70\ cm$ then the at $40^oC,$ the reading will show,

$L=70(1+\alpha _1\Delta T)$    $[\alpha$ ,of Brass , $\Delta T=40\ k]$
similarly , mercury expands to $70\ cm$ from initial length $Lo$
$\Rightarrow L=Lo(1+\alpha _2\Delta T)$   ($\alpha _2:$ mercury)
It gives :-
$Lo=\dfrac{70(1+\alpha _2\Delta T)}{(L+\alpha _2\Delta T)}=\dfrac{70(1+1.8\times Lo^{-5}\times 40)}{(1+1.8\times 10^{-4}\times40)}$
$Lo=69.55\ cm$

A Fahrenheit thermometer registers $107^{o}F$ while a faulty Celsius thermometer registers $42^{o}C$. Find the error in the later

  1. $0.37^{o}$

  2. $0.87^{o}$

  3. $0.67^{o}$

  4. $48$


Correct Option: C

The pressure of a gass filled in the bulb of a constant volume gas thermometer at temperatures $0^{o}C$ and $100^{o}C$ are $27.50\ cm$ and $37.50\ cm$ of $Hg$ respectively. At an unknown temperature the pressure is $32.45\ cm$ of $Hg$. Unknown temperature is

  1. $30^{o}C$

  2. $39^{o}C$

  3. $49.5^{o}C$

  4. $29.6^{o}C$


Correct Option: C

The height of the mercures column in a barometer provided with a bross scale corrected at $ 0^0C $ is obserevd to be 74.9 cm at $ 15^0 C $ . find the true height of the coulmn at $ 0^0 C/ \alpha _b=20 \times 10^{-6} /c^0 \gamma _Hg=175 \times 10^{-6}/c^0 . $

  1. 74.72 cm

  2. 79.92 cm

  3. 74.12 cm

  4. 72.64 cm


Correct Option: A

Mercury thermometers can be used to measure temperatures upto:

  1. $100^{o}C$

  2. $212^{o}C$

  3. $360^{o}C$

  4. $500^{o}C$


Correct Option: C
Explanation:

Mercury thermometer is based on the principle of change of volume with rise of temperature and can measure temperatures ranging from $-{30}^{\circ}$C to ${357}^{\circ}$C.

We cannot use mercury thermometer at low temperatures because:

  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.


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

  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


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?

  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


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 

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

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

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

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


Correct Option: A
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