Potassium and gold cathodes are used in a photoelectric-effect experiment. For each cathode, find: 1. The threshold frequency. 2. The threshold wavelength. 3. The maximum electron ejection speed if the light has a wavelength of 210 nm. 4. The stopping potential if the wavelength is 210 nm. Throughout this problem, be sure to use 6.63 X 10'34 J - s tor Planck's constant. The stopping potential in volts for potassium if the wavelength is 210 nm. Express your answer in volts. IE/EAZdJW StOPpotassium = 5-0 V V m Previous Answers Request Answer X Incorrect; Try Again; 28 attempts remaining V PartH The stopping potential in volts for gold if the wavelength is 210 nm. Express your answer in volts