Why does a flame appear yellow?

Where waves from multiple musical instruments add together such that there is completely deconstructive interference, are these nodes or antinodes?

One AM radio station that we can listen receive on our radios is broadcast at 640 MHz. Calculate the wavelength in meters of this radio wave. 

The isotope 146C has a half-life of 5,730 years. If a fossil is found to contain 1/8th the amount of carbon-14 as is typically found in a living plant or animal, how old is the fossil?

Magnets have a positively charged end and a negatively charged end.

Which quantum jump would most likely result in a blue line being emitted?

Which wire would result in the least electrical resistance?

An explosion is seen from a distant volcano, and 6 seconds later you hear the sounds from the explosion. How far away is the volcano?

If three different elements each have an atomic spectrum that includes a blue line, how can we know one element from another? (Choose the best answer)

When a light goes out in a room, other electrical devices continue to operate because most of the circuits in a house are wired in