A 2μF capacitor is charged to 12V and then is discharged through a 4 * 10 ^ 6 resistor. How long will it take for the voltage across the capacitor to drop to 3.0V?​

Aphoton is absorbed by an electron that is in the n = 3 state of a hydrogen atom, causing the hydrogen atom to become ionized. very far away from the nucleus, the released electron has a velocity of 750,000 m/s. what was the wavelength of the absorbed photon?