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प्रश्न
The energy of a photon is 2 eV. Find its frequency and wavelength.
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उत्तर
Given:
E = 2 eV = 2 × 1.6 × 10−19 = 3.2 × 10−19 J
To find:
- Frequency (ν)
- Wavelength (λ)
Formulae:
- E = hν
- λ = `c/ν`
Calculation:
i. Using formula (i),
v = `(3.2 xx 10^-19)/(6.63 xx 10^-34)`
= `(3.2 xx 10^15)/6.63`
= antilog {log (3.2) + log(1015) − log(6.63)}
= antilog {0.5051 + 15 − 0.8215}
= antilog {14.6836}
= 4.826 × 1014 Hz
The frequency of photons is 4.826 × 1014 Hz.
ii. Using formula (ii),
`λ = c/ν = (3 xx 10^8)/(4.826 xx 10^14)`
= antilog {log 3 − log 4.826} × 10−6
= antilog {0.4771 − 0.6836} × 10−6
= antilog {`overline1`.7935} × 10−6
= 0.6216 × 10−6m
= 6216 × 10−5 m
= 6216 Å
The wavelength of the photon is 6216 Å.
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संबंधित प्रश्न
Using the values of work function given in the following table, tell which metal will require the highest frequency of incident radiation to generate photocurrent.
Typical values of work function for some common metals
| Metal | Work function (in eV) |
| Potassium | 2.3 |
| Sodium | 2.4 |
| Calcium | 2.9 |
| Zinc | 3.6 |
| Silver | 4.3 |
| Aluminium | 4.3 |
| Tungsten | 4.5 |
| Copper | 4.7 |
| Nickel | 5.0 |
| Gold | 5.1 |
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