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Railway Tracks with Gaps and Ventilators in Houses

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Railway Tracks with Gaps and Ventilators in Houses

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Questions and Answers

Why are railway tracks constructed with gaps in between?

To increase the speed of trains
To reduce noise pollution
To allow for expansion due to heat (correct)
To prevent the tracks from rusting

What is the purpose of having ventilators in a house?

To block out sunlight
To allow hot air to escape and cool air to come in (correct)
To prevent rain from entering
To create a wind tunnel effect

Why is mercury used in a clinical thermometer?

To make the thermometer unbreakable
To add color to the thermometer
Because it is less expensive than other materials
To measure temperature accurately (correct)

Why do electric heaters have polished reflectors?

To generate more heat efficiently in front of the heater (A) Signup and view all the answers

What is expansion due to heat?

An increase in volume when heated (C) Signup and view all the answers

Which property of polished reflectors makes them ideal for use in electric heaters?

They reflect heat efficiently (C) Signup and view all the answers

What is the main purpose of gaps in railway tracks as mentioned in the text?

To allow the metal rails to expand due to heat (D) Signup and view all the answers

Why are metal rims on bullock cart wheels slightly smaller than the wooden wheel?

To allow for expansion and contraction with temperature changes (C) Signup and view all the answers

Which method of heat transfer is used in a thermos flask to minimize heat loss?

Conduction (A) Signup and view all the answers

What characteristic of heat allows for the conversion into mechanical energy?

Heat can be converted to other forms of energy (D) Signup and view all the answers

Why is the inner surface of the walls of a thermos flask silvered or polished?

To reflect radiated heat back into the flask (D) Signup and view all the answers

What is the purpose of having a vacuum between the double walls of a thermos flask?

To minimize heat loss due to convection (B) Signup and view all the answers