1) The longest wavelength of light that causes electrons to be ejected from the surface of a copper plate is 253 nm. What is the threshold frequency of the copper plate knowing that m_electron = 9.109 x 10^-25 mg?

2) If light with a wavelength of 260 nm shines on the copper plate, will electrons be ejected from the copper atoms? Explain.

Question

1) The longest wavelength of light that causes electrons to be ejected from the surface of a copper plate is 253 nm. What is the threshold frequency of the copper plate knowing that m_electron = 9.109 x 10^-25 mg?

2) If light with a wavelength of 260 nm shines on the copper plate, will electrons be ejected from the copper atoms? Explain.

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Accepted Answer

1) c = λν ⇒ ν₀ = $\frac{c}{λ_{0}}$ ⇒ ν₀ = $\frac{3.00 \times 10^{8}}{253 \times 10^{- 9}}$ = 1.19 x 10¹⁵ s^-1

2) ν= $\frac{c}{λ}$ ⇒ ν = $\frac{3.00 \times 10^{8}}{260 \times 10^{- 9}}$ = 1.15 x 10¹⁵ s^-1

ν < ν₀ ⇒ electrons won’t be ejected from the copper atoms.

Midterm 2 - Question 4 | General Chemistry 1

General Chemistry 1 - Midterm 2