物理熱轉移過程 DSE、CE 選擇題

1.

The figure below shows a solar cooker. Which of the following statements about its design is incorrect ?

Solar cooker: sunlight onto a glass cover, board P reflecting, pot Q inside case R

2.

Photograph of an aluminium heat sink with fins

The above figure shows the aluminium heat sink of an audio amplifier which is used to transfer heat away from the components inside the amplifier. Which of the following statements about the heat sink is/are correct ?

(1)The heat sink is made of aluminium so that it can transfer heat away faster by conduction.

(2)The heat sink is silver in colour so that it can transfer heat away faster by radiation.

(3)The heat sink has a fin-like design to increase the surface area so that it can transfer heat away faster by conduction to air.

3.

The diagram below shows the structure of a cake.

Cross-section of a cake showing sponge cake, whipped egg white with many air bubbles, and ice-cream inside

The ice-cream inside the cake does not melt when it is baked in an oven. Which of the following statements are possible reasons for this phenomenon ?

(1)The whipped egg white is a poor conductor of heat.

(2)The whipped egg white is a good radiator of heat.

(3)The sponge cake is a poor conductor of heat.

4.

Vacuum flask with cork stopper, hot liquid, double glass walls with vacuum between, and surfaces P and Q

The figure shows a vacuum flask with two glass walls. Which of the following statements are correct ?

(1)The surfaces

P

and

Q

are painted silvery to reduce heat loss.

(2)The cork stopper reduces heat loss by conduction and convection.

(3)The vacuum between the double glass walls reduces heat loss by radiation.

5.

The photograph shows a hot potato wrapped by shiny aluminium foil. By what means can the foil help reducing the rate of energy lost from the potato to the surroundings ?

(1)conduction

(2)convection

(3)radiation

Photograph of a potato wrapped in shiny aluminium foil