Two different monochromatic light sources, one yellow (580 nm) and one violet (4

Question

Two different monochromatic light sources, one yellow (580 nm) and one violet (425 nm), are used in a photoelectric effect experiment. The metal surface has a photoelectric threshold frequency of 6.20 x 10^14 Hz. (A) Are both sources able to eject photoelectrons from the metal? Explain. (B) How much energy is required to eject an electron from the metal? (Use h = 4.136 x 10^-15 eV•s) Two different monochromatic light sources, one yellow (580 nm) and one violet (425 nm), are used in a photoelectric effect experiment. The metal surface has a photoelectric threshold frequency of 6.20 x 10^14 Hz. (A) Are both sources able to eject photoelectrons from the metal? Explain. (B) How much energy is required to eject an electron from the metal? (Use h = 4.136 x 10^-15 eV•s)

Explanation / Answer

Given,

A)lambda(yellow) = 580 nm ; lambda(violet) = 425 nm

f(cutoff) = 6.2 x 10^14 Hz

f(yellow) = c/lambda(yellow) = 3 x 10^8/580 x 10^-9 = 5.17 x 10^14 Hz

f(violet) = c/lambda(violet) = 3 x 10^8/425 x 10^-9 = 7.06 x 10^14 Hz

v(violet) > f(cutoff) > f(yellow)

The frequency of violet light overcomes the cutoff frequency, so light source with violet light will be able in ejecting a photoelectron.

B)The amount of energy required to eject the electron will be given by:

E = hf

E = 4.136 x 10^-15 x 6.2 x 10^14 = 2.56 eV

Hence, E = 2.56 eV

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.