Question

Photoelectrons from a material with a binding energy of 2.71 eV are ejected by 420-nm photons. Once ejected, how long does it take these electrons to travel 2.50 cm to a detection device?

a)1.17 x 10^-15 s
b)2.34 x 10^-15 s
c)3.51 x 10^-15 s
d)4.68 x 10^-15 s

Answer 1

The time it takes for the ejected photoelectrons to travel 2.50 cm can be calculated using the speed of light and the energy of the photons. The correct answer is 1.17 x 10^-15 s.

Step-by-step explanation:

The time it takes for the ejected photoelectrons to travel 2.50 cm can be calculated using the speed of light and the energy of the photons. First, convert the wavelength of 420 nm to meters by dividing by 10^9 (since nm is 10^-9 m). The energy of the photons can be calculated using the equation E = hc/λ, where h is Planck's constant (6.626 x 10^-34 J·s), c is the speed of light (3.00 x 10^8 m/s), and λ is the wavelength in meters. Then, divide the distance of 2.50 cm by the speed of light to calculate the time it takes for the electrons to travel to the detection device. The correct answer is option (a) 1.17 x 10^-15 s.