Find the force of gravity between two physics students that have masses of 74.0 kg and 82.5 if they are sitting 0.95 m apart

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?

Which diagram correctly demonstrates the various forces acting on a ball moving horizontally with some speed?

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.