What energy conversion takes place in an internal combustion engine?

a. thermal energy is converted into heat and work.

b. thermal energy is
converted into work.

c. chemical energy is
converted into heat and work.

d. chemical energy is converted into work.

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?