Which energy conversion takes place when a solar cell is used to light a street lamp?
a) solar energy → light energy
b) solar energy → electric energy → light and heat energy
c) solar energy → light and heat energy
d) heat energy → light energy
e) heat energy → light energy → electric energy

Answer;

B) solar energy → electric energy → light and heat energy

Explanation;

- From the law of conservation of energy, energy can never be created or destroyed, however energy may be converted from one form to another. The devices that transform energy from one form to another are called transducers, such as solar cell, generator, street lam, light bulb, etc.

-Solar cells also called the photovoltaic cells are devices that transform light energy directly into electrical energy.

-A street lamp on the other hand converts electrical energy into heat and light energy.

cats appear to have glowing cat eyes because the back of their eyeballs includes a special reflective surface called the tapetum lucidum. this lets them see better during the night, giving them a much better vision.

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.