Physics questions!! Need answers =D?

Question

A drop of liquid falls on a student’s skin and quickly evaporates.
What is the effect on the skin and the reason?
A The skin cools because the most energetic molecules escape from the liquid.
B The skin cools because the most energetic molecules remain in the liquid.
C The skin warms because the most energetic molecules escape from the liquid.
D The skin warms because the most energetic molecules remain in the liquid.

A knife is being sharpened on a rotating sharpening stone. A spark flies off and lands on the operator’s hand. The spark is very hot, very small piece of metal. The operator feels nothing.
What does this show about the piece of metal?
A It has a high thermal capacity.
B It has low thermal capacity.
C It is a good conductor of heat.
D It is a poor conductor of heat.

How does heat from the sun reach the Earth?
A Conduction only
B Convection
C Radiation only
D Conduction, convection, and radiation

Answer 1

A drop of liquid falls on a student’s skin and quickly evaporates.
What is the effect on the skin and the reason?

A is the answer. The most energetic molecules leave the skin and thus reduce the temperature of the skin locally.


A knife is being sharpened on a rotating sharpening stone. A spark flies off and lands on the operator’s hand. The spark is very hot, very small piece of metal. The operator feels nothing.
What does this show about the piece of metal?

B It has low thermal capacity. and hence the skin doesn't feel the heat or get burnt,

How does heat from the sun reach the Earth?

C Radiation only

It reaches the earth by radiation only since conduction and convection need a material medium and sunlight reaches earth after passing through millions of miles in space. After the sunlight falls on earth, heating is by conduction and convection (of the air and water) in addition to radiation.

Answer 2

Good questions.
1) A. Doesn't it makes sense that when u pour liquid onto your skin, its to cool it? That's because the evaporation of water means that the water molecules have gained enough energy from your skin to jump up into the air.
2) C? I'm not sure actually.
3) C. If conduction (which implies contact), then we would all be dead. Convection refers to liquids.

Answer 3

good questions. a million) A. would not it incredibly is sensible that as quickly as u pour liquid onto your pores and skin, its to kick back it? it incredibly is by technique of the fact the evaporation of water ability that the water molecules have gained sufficient ability out of your pores and skin to bounce up into the air. 2) C? i'm uncertain certainly. 3) C. If conduction (meaning touch), then we'd all be ineffective. Convection refers to drinks.

Answer 4

You should really stop posting your homework all over Answers.

Edit: I mean, don't get me wrong, there's nothing wrong with asking a question or two if you're confused. That's what we're here for :) but just mechanically typing in ALL of your multiple-choice homework? That's just dishonest. You probably haven't even looked at the questions.

Answer 5

Yep, you should read your book. Chances are it has the answers word-for-word.

Answer 6

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