This question can likely be answered using the formula E=hc/w where w is wavelength, h is Planck's constant, c is the speed of light, and E is energy in Joules. 5 electrons are emitted when calcium is flashed with light of wavelength 340 nm and intensity of 50 percent.
Remove the hog-rings as you roll the cover up over the seat. If your seat has a hard back, there will be a series of screws along the bottom that hold the bottom of the hard back to the seat. Unscrew these, and then pull open the hard back slightly to determine if the hardback needs to be slid up or down to be removed.
Pumice can be used to remove copper rings from the inside of a toilet. Put on a pair of nonporous cleaning gloves to start. Then simply rub the pumice stone over the ring using a scrubbing motion. Repeat until the ring is gone. You can use the stone in combination with toilet cleaner for more stubborn stains.