Is a typical refrigerator door made of iron or aluminum? explain.

Name three different units of energy used to measure heat and describe what type of situations each is usually used.

Aphoton is absorbed by an electron that is in the n = 3 state of a hydrogen atom, causing the hydrogen atom to become ionized. very far away from the nucleus, the released electron has a velocity of 750,000 m/s. what was the wavelength of the absorbed photon?

Which of the following forces require physical contact? tension air resistance friction magnetic force applied force