In emission,
a) an electron moves from an excited state to a lower energy state, and energy is released.
b) an electron moves from an excited state to a lower energy state, and energy is absorbed.
c) an electron moves from a lower energy state to an excited state, and energy is released.
d) an electron moves from a lower energy state to an excited state, and energy is absorbed.

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

Acertain radio station broadcasts radio waves that have a wavelength of 298cm what is its broadcast frequency?

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. they are charged to ±10 nc. what is the electric field strength between the disks? a proton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?