A hydrogen atom initially in the n = 2 level emits a photon and ends up in the ground state. (a) What is the energy of the emitted photon? (I got 10.2 eV) (b) If this atom then absorbs a second photon and returns to the n = 2 state, what must the energy of this photon be

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600