Question 4

During very cold weather, ice can form on the surface of puddles of water. If the ice layer is found to be thickening at its lower surface, then how is the thermal energy been transferred?

Ans: Convected away from the ice through the water.

Question 3

An unlit match is held near to an extremely hot Bunsen flame. Why does the match not get hot enough to light?

Ans: Air is a bad conductor of heat. Thus, there is not enough heat being transferred from the Bunsen burner to the unlit match.

Wrong Assumptions:
1. The flame is not hot enough.
2. The flame does not radiate any heat sideways.
3. A match can only be lit by striking it on a rough surface.

Question 2

Which of the following is true?
1. Dog drools(salivates) to allow heat loss by evaporation.
2. Elephant sprays water over its body to allow heat loss by evaporation.
3. Jack rabbit has enormous ears with many blood vessels to dissipate thermal energy faster.
4. Camel has big humps to store water so that it can dissipate thermal energy by convection.

Ans: 1, 2, 3 are correct.

Question 1

Some steamboat restaurants use paper pots for their customers to boil the food themselves.
What is the reason for the paper not to catch fire when in contact with the flame?


Ans:
The paper is thin and therefore heat is conducted quickly to the water in the paper pot.
The burning temperature of the paper is higher than the boiling point of water.