An ultraviolet light beam having a wavelength of 130 nm is incident on a molybdenum surface with work function of 4.2 eV.What is the stopping potential? (h = 6.63 x 10^-34J*s,c = 3.00 x 10⁸ m/s,1 eV = 1.6 x 10^-19 J,and 1 nm = 10^-9 m) A)1.3 V B)3.5 V C)5.4 V D)11.9 V

Question

Quizplus · Accepted Answer

The energy of a photon can be calculated using the equation E = hc/λ, where h is Planck's constant, c is the speed of light, and λ (lambda) is the wavelength of the photon. Plugging in the given values, we get:

E = (6.63 x 10^-34 J*s)(3.00 x 10^8 m/s)/(130 x 10^-9 m)
E = 1.52 x 10^-18 J

The stopping potential can be calculated using the equation V_stop = (E_photon - W)/e, where E_photon is the energy of the photon, W is the work function, and e is the elementary charge. Plugging in the given values, we get:

V_stop = (1.52 x 10^-18 J - (4.2 eV)(1.6 x 10^-19 J/e))/(1.6 x 10^-19 C/e)
V_stop ≈ 5.4 V

Therefore, the best choice is C, with a stopping potential of 5.4 V.

An Ultraviolet Light Beam Having a Wavelength of 130 Nm