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प्रश्न
The work function of a metal is 4.2 eV. Its threshold wavelength will be ______.
विकल्प
4000 Å
3500 Å
2959 Å
2500 Å
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उत्तर
The work function of a metal is 4.2 Ev. Its threshold wavelength will be 2959 Å.
Explanation:
`lambda = (hc)/phi_0 = (6.63 xx 10^-34 xx 3 xx 10^8)/(4.2 xx 1.6 xx 10^-19`
= 2959.8 × 10−10
≈ 2959 Å
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