9th Physics chapter 7 Constructed response questions
9th Physics chapter 7 Constructed response questions. We will answer only revised smart syllabus for class 9th physics.
7.1 Is kinetic molecular theory of matter applicable to the plasma state of matter? Describe briefly.
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7.2 Why is mercury usually preferred to alcohol as a thermometric liquid?
We use Mercury as thermometric liquid due to its wide temperature range. It expands uniformly with temperature and it does not stick to glass. Its boiling point is also high. It does not freeze easily.
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7.3 Why is water not suitable for use in thermometers? Without calculations, guess what is equivalent temperature of 373 k on Celsius and Fahrenheit scales?
Water gives a narrow range of temperature. Its melting point is 0 degree Celsius and boiling point is 100 degree Celsius. It expands evenly with temperature.
$$Celsius\\T_c=373-273\\=100^\circ C\\Fahrenheit\\T_f=\frac95\times100+32\\=212^\circ F$$
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7.4 Mention tow ways in which the design of a liquid-in-glass thermometer may be altered to increase its sensitivity.
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7.5 One litre of water is heated by a stove and its temperature rise by 2 degree Celsius. If two litres of water is heated on the same stove for the same time, what will be then rise in temperature?
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7.6 Why are there no negative numbers on the Kelvin scale?
There will be no negative number on Kelvin scale because temperature cannot be below absolute zero (0 k). Kelvin scale starts from absolute zero.
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7.7 Comment on the statement. “A thermometer measures its own temperature.”
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7.8 There are various objects made of cotton, wood, plastic, metals, etc. In a winter night, compare their temperatures with the air temperature by touching them with your hand.
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7.9 Which is greater: an increase in temperature 1 degree Celsius or 1 degree Fahrenheit?
1 degree Celsius is greater than 1 degree Fahrenheit because 1 degree Celsius corresponds to 1.8 degree Fahrenheit.
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7.10 Why would not you expect all the molecules in a gas to have the same speed?
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7.11 Does it make sense to talk about the temperature of a vacuum?
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7.12 Comment on the statement: “A hot body does not contain heat”.
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7.13 Discuss whether the Sun is matter.
Yes, sun is matter. Sun consists of 4th state of matter i.e Plasma. It has mainly Hydrogen and Helium atoms.
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Below, We give some important links.
