Electrons in excited hydrogen atoms are in the
n = 3 energy level. how many different photon
frequencies could be emitted as the atoms return
to the ground state?
(1) 1 (3) 3
(2) 2 (4) 4

Which statement correctly describes a step-up transformer? a. it increases the amount of electric energy available. b. it increases the voltage of an electric current. c. it changes direct current into alternating current. d. it has more loops of wire in its primary coil.

Tall pacific coast redwood trees can reach heights of about 100 m. if air drag is negligibly small, how fast is a sequola cone moving when it reaches the ground f it dropped from the top of a 100 m tree?

What is the rate of 12 liters of water moving through a water hose in 4.0 minutes?