Physics questions..please help?

Question

A clock radio is rated as 30 W of power output. If the radio also draws 30 W at 120 V, which will the current draw be?

0.25 A

4 A

3,600 A

0.5 A

What is the transfer of heat from a stove burner to a pan on the burner called?

conduction

convection

radiation

When you rub a match against a rough surface, fire results, giving off light and heat. The law of conservation of energy says that energy cannot be created. How can you explain the fire seeming to come from nowhere?

The energy was stored in chemical bonds before it became heat and light.

Matches are made to take up energy from surfaces.

The energy started out as the sound energy of the rubbing match.

Answer 1

Power = current x voltage

P=I V

I =P/V=30/120=0.25A

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conduction

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The energy was stored in chemical bonds before it became heat and light.

Answer 2

A clock radio is rated as 30 W of power output. If the radio also draws 30 W at 120 V, which will the current draw be?

Impossible to answer. If the radio is delivering 30 watts of (audio) output, then it must be consuming a lot more than 30 watts of AC power, yet the second part says it draws only 30 watts of AC power.

If I had to pick an answer, it would be 0.5 amps, which is 60 watts.

What is the transfer of heat from a stove burner to a pan on the burner called?

conduction and radiation, both are present.

When you rub a match against a rough surface, fire results, giving off light and heat. The law of conservation of energy says that energy cannot be created. How can you explain the fire seeming to come from nowhere?  It's chemical energy that results from the chemical reaction between the chemicals on the match head.

The energy was stored in chemical bonds before it became heat and light.