Asmall sphere of mass 2 kg is attached to the end of a cord of length 2 m and rotated in a vertical circle about a fixed point o. determine the tension in the cord at the uppermost point of the trajectory if the speed at this point is 8 m/s. use g=9.8 m/s2. report your answer as a positive number in newtons.

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?