Wild World: Solar Cell Quiz
by Staff
Solar cells are on everything from pocket calculators to the roofs of buildings. So exactly how do they turn light into energy?

Solar cells use _____ to turn light into energy.

  • electromagnets
  • semiconductors
  • superconductors

Silicon works as a semiconductor because:

  • Added impurities allow electrons to move freely.
  • Its molecular structure is a lot like that of copper.
  • It forms conductive crystals.

The phosphorous in a solar cell's semiconductor:

  • provides free electrons
  • bonds with unpaired electrons
  • stabilizes the silicon matrix

The boron in a solar cell's semiconductors:

  • produces extra electrons
  • repels electrons
  • attracts electrons

When you combine P-type and N-type silicon in a solar cell:

  • Electrons rush from N to P, leaving the N side empty.
  • Electrons at the N-P junction eventually form a barrier.
  • Nothing happens.

Once equilibrium is reached between the N and P sides of a cell, the cell acts as:

  • a transistor
  • a capacitor
  • a diode

When light hits a solar cell, electrical current comes from:

  • electrons traveling from the N side to the P side along a circuit
  • electrons traveling from the N side to the P side across the N-P junction
  • electrons traveling from the P side to the N side along a circuit

A solar cell can only absorb 15 to 25 percent of the sun's energy because:

  • Not all wavelengths of light create the right reaction in the cell.
  • There's too much resistance inside the semiconductor.
  • both A and B

A typical photovoltaic array has 36 cells. If one is shaded, power production drops by:

  • 10 percent
  • 25 percent
  • 50 percent

To use solar energy in your home, you need:

  • a substation
  • an inverter
  • a converter