What's the main reason why people use graphs

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.