JEE Main · 2022 · 28 Jun 2022 · Shift 1 · Atomic Structure

If the work function of a metal is

6.63 \times 1 0^{- 19}

J, the maximum wavelength of the photon required to remove a photoelectron from the metal is ______ nm. (Nearest integer)
[Given:

h = 6.63 \times 1 0^{- 34}

J s, and

c = 3 \times 1 0^{8}

m s

^{- 1}

]

Answer: 300

Solution

The work function

ϕ

is the minimum energy required to remove an electron. For the threshold wavelength (maximum wavelength):

ϕ = \frac{h c}{λ}

Rearranging:

λ = \frac{h c}{ϕ} = \frac{6.63 \times 1 0 ^{- 34} \times 3 \times 1 0 ^{8}}{6.63 \times 1 0 ^{- 19}}

λ = 3 \times 1 0^{- 7}

m =

300

JEE Main · 2022 · 28 Jun 2022 · Shift 1 · Integer answer