Answer:
a) f = 3.02x10¹⁵ s⁻¹, and λ = 99.4 nm.
b) 99.4 nm
Explanation:
a) The energy of radiation is given by:
E = h*f
Where h is the Planck constant (6.626x10⁻³⁴ J.s), and f is the frequency. To have the highest frequency, the energy must be the highest too, because they're directly proportional. So we must use E = -E1 = 20x10⁻¹⁹ J
20x10⁻¹⁹ = 6.626x10⁻³⁴xf
f = 3.02x10¹⁵ s⁻¹
The wavelenght is the velocity of light (3.00x10⁸ m/s) divided by the frequency:
λ = 3.00x10⁸/3.02x10¹⁵
λ = 9.94x10⁻⁸ m = 99.4 nm
b) To have the shortest wavelength, it must be the highest energy and frequency, so it would be the same as the letter a) 99.4 nm.