Question

1. Wood conducts heat very poorly—it has a very low conductivity. Does wood still have a low conductivity if it is hot?A. Yes

B. No2. Could you quickly and safely grasp the wooden handle of a pan from a hot oven with your bare hand? A. Yes
B. No3. Although the pan handle is hot, is much heat conducted from it to your hand if you grasp it briefly? A. Yes
B. No4. Why would it be a poor idea to do the same with an iron handle? A. Yes
B. NoExplain.

Answer 1

1. A.Yes

2. A.Yes

3. A.Yes

4. A.Yes

Step-by-step explanation:

1. Wood conducts heat poorly, and yes it has the same property of conductivity even when it is hot. Its thermal conductivity does not changes with temperature if it is uniformly dry and uniformly dense. Its thermal conductivity increases with density and moisture content; thus, light & dry woods are better insulators.

2. Yes, one can grasp quickly and safely the wooden handle of a pan from a hot oven with ones bare hand for a short time.

3. Yes, although the pan handle is hot, not much heat conducted from it to our hand if we grasp it briefly because it has low value of thermal conductivity.

In other words it has high resistance to the flow of heat via conduction. So, the rate of heat transfer is slow, providing us a considerable frame of time to hold it safely.

The explanation can be justified by the Fourier's Law of Thermal Conduction:

Mathematically:

`q=-kA(dT)/(dx)`

where:

• q= rate of heat transfer through conduction in the material of thermal conductivity k

• dT= temperature difference across the ends of material through which the heat is being conducted

• dx= thickness of the ends of material across which the heat is being conducted.

-ve sign is to express that the direction of heat flow is in the direction of decreasing temperature.

4. Yes, it would be a poor idea to do the same with an iron handle because it has higher thermal conductivity which means that more heat is transferred in a short span of time that can cause burn to the bare hands.