(Help) when nearly vertical rays of solar energy strike a region of the earth that area has warm temperatures what region of the earth gets nearly vertical rays of solar energy year around? A) United States
B) Australia
C) North and South Poles
D) Equator

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?