MCQ Questions for Class 7 Physics Heat Quiz 10

The standard fixed point for temperature measurement is used these days is :

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melting point of ice at S.T.P.
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that temperature at which ice, water and water vapour coexist
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that temperature at which pure ice and pure water coexist
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none of the above

Four arrangements to measure temperature of ice in beaker with laboratory thermometer are shown in Figure (a. b. c and d).
Which one of them shows the correct arrangement for accurate measurement of temperature?

A thermometer is graduated in:

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Kelvin
0%
$^\circ C$
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$g$
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$cm$

Explanation

The thermometer is a device that measures temperature. Its graduation is done in

^{\circ} C

$^{\circ}C$ or Fahrenheits.

Select the correct alternative
The symbol of degree Celsius is

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$^\circ C$
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$^\circ F$
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$K$
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$^\circ K$

Explanation

The symbol of degree Celsius is

^{\circ} C

$^\circ C$

Option A.

Figure (a, b, c, d) shows the readings on four different thermometers. Indicate which of the reading shows the normal human body temperature?

Explanation

The correct answer is option (c). The normal human body temperature is

37^{o} C

$37^{o}C$ .

Write 'true' or 'false' for each statement:

Medium is necessary for the transfer of heat by radiation.

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True
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False

Choose the correct alternative:

In the process of convection, heat travels

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sideways
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downwards
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upwards
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in all direction

The velocity of heat radiation in vacuum is

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Equal to that of light
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Less than that of light
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Greater than that of light
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Equal to that of sound

Explanation

The velocity of heat radiation in the vacuum is

e q u a l

$equal$ to that of light.

Snow is more heat-insulating than ice, because

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Air is filled in porous of snow
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Ice is more bad conductor than snow
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Air is filled in porous of ice
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Density of ice is more

The layers of the atmosphere are heated through

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Convection
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Conduction
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Radiation
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(b) and (c) both

A thermos flask is polished well

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To make attractive
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For shining
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To absorb all radiations from outside
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To reflect all radiations from outside

Woollen clothes are used in winter season because woollen clothes

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Are good sources for producing heat
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Absorb heat from surroundings
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Are bad conductors of heat
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Provide heat to body continuously

Explanation

In winter, the temperature of the surrounding is low compared to the body temperature

{37.4}^{\circ} C

$37.4 ^\circ C$ . Since woollen clothes are bad conductors of heat, so they keep the body warm .

Answer the question:
The thermometer in the diagram has no scale.
Where must the bulb be placed so that

0^{\circ} C

$0^\circ C$ can be marked on the stem ?

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in a freezer
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in pure boiling water
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in pure cold water
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in pure melting ice

Explanation

To mark

0^{o} C

$0^o\,C$ on thermometer, we need to put it in where temperature is

0^{o} C

$0^o \,C$

As we know that Temperature in pure melting ice is

0^{o} C

$0^o \,C$ ,

so we should put thermometer in pure melting ice to mark on scale.

Hence option D is correct

Choose whether true or false:-
Sense of touch is an appropriate measure to determine the temperature of any object.

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True
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False

Which of these we could identify as cold with our sense of touch?

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Cup of hot coffee
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Hot tea
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Ice
0%
A glass of water

How is temperature measured?

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By sense of touch
0%
By looking at objects
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Through a thermometer
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None of these

Explanation

Temperature is measured by a device called thermometer, thus option

C

$C$ is correct.

A reliable measure of the hotness of an object is ____________

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Temperature
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Thermometer
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Sense of touch
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None of these

Explanation

A reliable measure of the
hotness of an object is its
temperature thus option

A

$A$ is correct.

India has adopted _______ scale.

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Fahrenheit scale
0%
Celsius scale
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Kelvin Scale
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None of these

Explanation

India has adopted the celsius scale, thus option

B

$B$ is correct.

Choose whether true or false:-
Clinical thermometers can be used to measure any range of temperature.

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True
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False

Choose whether true or false:-
Same type of thermometer is used everywhere.

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True
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False

Choose whether true or false:-
Digital thermometers are a version of clinical thermometers.

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True
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False

The movement of water being heated in a pot on a stove is an example of

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conduction
0%
convection
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radiation
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condensation

A student took an iron rod and a wooden rod and wrapped each of them in a piece of paper. These were then heated as shown. It was found that the paper around the iron rod does not burn whereas the one around the wooden rod catches fire.It is because

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Candle, in case of iron rod, is nearer to the paper
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Wood being a bad conductor of heat, takes away all the heat
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Iron being a good conductor of heat, conducts away the heat give to the paper
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Paper, in first case, is thicker

If the temperature of a hot body is increased by 50% then the increase in the quantity of emitted heat radiation will be

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125%
0%
200%
0%
300%
0%
400%

Explanation

let us assume initial Temperature $T_1=T$ then final will be

$T_2=\dfrac{50}{100}T+T=\dfrac{150}{100}T=\dfrac{15}{10}T$

energy radiated

$e_1=\sigma A T_1^4\quad \left(1\right)$

$e_2=\sigma A T_2^4\quad \left(2\right)$

$\%$ increase in radiation

$=\dfrac{e_2-e_1}{e_1}\times 100$

$=\dfrac{\sigma A T_2^4-\sigma A T_1^4}{\sigma A T_1^4}\times 100$

$\dfrac{\left(\dfrac{15}{10}T\right)^4-T^4}{T^4}\times 100$

$\dfrac{15^4-10^4}{10^4}\times 10^2$

$\dfrac{50625-10000}{10^2}$

$=406.25$

$\approx 400\%$

Hence

(d)

$(d)$ option is correct.

Boojho has three thermometers as shown in above Figure. He wants to measure the temperature of his body and that of boiling water. Which thermometer (s) should he choose?

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Thermometer (i) or (iii) for measuring body temperature and (ii) for measuring the temperature of boiling water.
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Thermometer (i) for measuring temperature of both.
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Thermometer (ii) for measuring temperature of both.
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Thermometer (iii) for measuring temperature of both.

Two thermometers are used to record the temperature of a room and the bulb of one is wrapped in a wet hanky.

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The temperature recorded by both will be same
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The temperature recorded by the wet-bulb thermometer will be greater than that recorded by the other
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The temperature recorded by dry-bulb thermometer will be greater than that recorded by the other
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None of the above

A metal spoon is placed in one of two identical cups of hot coffee. Why does the cup with the spoon have a lower temperature after a few minutes ?

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Energy is removed from the coffee mostly by conduction through the spoon.
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Energy is removed from the coffee mostly' by convection through the spoon.
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Energy is removed from the coffee mostly by radiation through the spoon.
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None of these

Mercury is often used in clinical thermometers. Which one of the following properties of mercury is not a reason for this ?

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The coefficient of the thermal expansion is large
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It is shiny
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It is a liquid at room temperature
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It has high density.

Two thermometers are constructed in such a way that one has a spherical bulb and the other has elongated cylindrical bulb. The bulbs are made of same material and thickness. Then :

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spherical bulb will respond more quickly to temperature changes
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cylindrical bulb will respond more quickly to temperature changes.
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both bulbs will respond same to temperature changes
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none of both bulbs respond to temperature changes

Which of the following are the correct units of temperature?

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K or Kelvin
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Degree Celsius
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Metre
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Inch

CBSE Questions for Class 7 Physics Heat Quiz 10 - MCQExams.com

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Practice Class 7 Physics Quiz Questions and Answers

CBSE Questions for Class 7 Physics Heat Quiz 10 - MCQExams.com

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Practice Class 7 Physics Quiz Questions and Answers

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