Question

Light from the sun allows a solar cell to move electrons from the positive to the negative terminal, doing 2.8×10⁻¹⁹ J of work per electron. What is the work done by 1 mole of electrons?

1) 2.8×10⁻¹⁹ J
2) 2.8×10⁻⁵ J
3) 2.8×10⁻²³ J
4) 2.8×10⁻¹ J

Answer 1

To determine the work done by 1 mole of electrons in a solar cell, multiply the work done per electron by Avogadro's number. The correct answer is 2.8×10⁻µ J, which is option 2.

Step-by-step explanation:

The work done by light from the sun on a solar cell to move electrons from the positive to the negative terminal is given as 2.8×10⁻¹⁹ J per electron. To find the work done by 1 mole of electrons, we use Avogadro's number, which is approximately 6×10²³ electrons per mole. Since the work is done per electron, we multiply the work per electron by the total number of electrons in one mole.

The calculation will be as follows:
2.8×10⁻¹⁹ J/electron × 6×10²³ electrons/mole = 1.68×10⁻¹⁵ J/mole

However, the number should be represented with only two significant figures to match the precision of the given data, which means the work done by one mole of electrons is 2.8×10⁻µ J.

Therefore, the correct answer is 2) 2.8×10⁻µ J.