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Light of wavelength 500 nm is incident on a metal with work function 2.28 eV. The wavelength of the emitted electron is:
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- < 2.8 × 10-9 m
- ≥ 2.8 × 10-9 m
- ≤ 2.8 × 10-12 m
- < 2.8 × 10-10 m
Correct Option: B
Given : Work function φ of metal = 2.28 eV
Wavelength of light λ = 500 nm = 500 × 10–9 m
| KEmax = | - φ | λ |
| KEmax = | - 2.28 | 5 × 10-7 × 1.6 × 10-19 |
KEmax = 2.48 – 2.28 = 0.2 ev
| λmin = | = | |||
| p | √2 m(KE)max |
| = | × 10-34 | |
| 3 | ||
| √2 × 9 × 10-31 × 0.2 × 1.6 × 10-19 | ||
| λmin = | × 10-9 | 9 |
= 2.80 × 10–9 nm
∴ λ ≥ 2.8 × 10–9 m
