What was discovered in 1965 and is believed to be leftover thermal energy from the Big Bang? A. Red shift

B. The Eagle Nebula

C. The Doppler effect

D. Background Radiation

Kate is working on a project in her tech education class. she plans to assemble a fan motor. which form of energy does the motor convert most of its electric energy into? a. light energy b. motion energy c. sound energy d. thermal energy

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?

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87