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प्रश्न
If the wavelength of light in an experiment on photoelectric effect is doubled,
(a) photoelectric emission will not take place
(b) photoelectric emission may or may not take place
(c) the stopping potential will increase
(d) the stopping potential will decrease
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उत्तर
(b) photoelectric emission may or may not take place
(d) the stopping potential will decrease
For photoelectric effect to be observed, wavelength of incident light should not be more than the largest wavelength called threshold wavelength `(λ_0)`. If the wavelength of light in an experiment on photoelectric effect is doubled and if it is equal to or less than the threshold wavelength, then photoelectric emission will take place. If it is greater than the threshold wavelength, photoelectric emission will not take place. The photoelectric emission may or may not take place.Photoelectric emission depends on the wavelength of incident light.
Hence, option (b) is correct and (a) is incorrect.
From Einstein's photoelectric equation,
`eV_0 = (hc)/λ_0 - varphi`,
where V0 = stopping potential
`λ_0` = threshold wavelength
h = Planck's constant
`varphi` = work-function of metal
It is clear that
`V_0 ∝ 1/λ_0`
Thus, if the wavelength of light in an experiment on photoelectric effect is doubled, its stopping potential will become half.
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संबंधित प्रश्न
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- Can you explain how photoelectric effect was observed instantaneously?
The graph shows the variation of photocurrent for a photosensitive metal
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- Draw this graph for three different values of frequencies of incident radiation ʋ1, ʋ2 and ʋ3 (ʋ3 > ʋ2 > ʋ1) for the same intensity.
- Draw this graph for three different values of intensities of incident radiation I1, I2 and I3 (I3 > I2 > I1) having the same frequency.
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