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Threshold wavelength for photoelectric emission from a metal surface is 5200 Å. Photoelectrons will be emitted when this surface is illuminated with monochromatic radiation from
- a)1 W IR lamp
- b)50 W UV lamp
- c)50 W IR lamp
- d)10 W IR lamp
Correct answer is option 'B'. Can you explain this answer?
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Most Upvoted Answer
Threshold wavelength for photoelectric emission from a metal surface i...
Explanation:
Threshold wavelength for photoelectric emission from a metal surface is 5200 Å. This means that the minimum energy required to eject an electron from the metal surface is equivalent to a photon of wavelength 5200 Å.
When the metal surface is illuminated with monochromatic radiation, only photons with energy greater than or equal to the work function of the metal can cause photoelectric emission.
Now, let's consider each option given in the question:
A) 1 W IR lamp: Infrared radiation does not have enough energy to cause photoelectric emission from a metal surface, regardless of the power of the lamp. Therefore, this option is incorrect.
B) 50 W UV lamp: Ultraviolet radiation has higher energy than infrared radiation and can cause photoelectric emission from the metal surface if its wavelength is less than or equal to the threshold wavelength. The power of the lamp is not relevant in this case. Since the wavelength of UV radiation is shorter than 5200 Å, this option is correct.
C) 50 W IR lamp: As mentioned earlier, infrared radiation does not have enough energy to cause photoelectric emission from the metal surface, regardless of the power of the lamp. Therefore, this option is incorrect.
D) 10 W IR lamp: Similar to option A, this option is also incorrect as infrared radiation does not have enough energy to cause photoelectric emission from the metal surface.
In conclusion, option B (50 W UV lamp) is the correct answer as it provides enough energy to cause photoelectric emission from the metal surface.
Threshold wavelength for photoelectric emission from a metal surface is 5200 Å. This means that the minimum energy required to eject an electron from the metal surface is equivalent to a photon of wavelength 5200 Å.
When the metal surface is illuminated with monochromatic radiation, only photons with energy greater than or equal to the work function of the metal can cause photoelectric emission.
Now, let's consider each option given in the question:
A) 1 W IR lamp: Infrared radiation does not have enough energy to cause photoelectric emission from a metal surface, regardless of the power of the lamp. Therefore, this option is incorrect.
B) 50 W UV lamp: Ultraviolet radiation has higher energy than infrared radiation and can cause photoelectric emission from the metal surface if its wavelength is less than or equal to the threshold wavelength. The power of the lamp is not relevant in this case. Since the wavelength of UV radiation is shorter than 5200 Å, this option is correct.
C) 50 W IR lamp: As mentioned earlier, infrared radiation does not have enough energy to cause photoelectric emission from the metal surface, regardless of the power of the lamp. Therefore, this option is incorrect.
D) 10 W IR lamp: Similar to option A, this option is also incorrect as infrared radiation does not have enough energy to cause photoelectric emission from the metal surface.
In conclusion, option B (50 W UV lamp) is the correct answer as it provides enough energy to cause photoelectric emission from the metal surface.
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Community Answer
Threshold wavelength for photoelectric emission from a metal surface i...
Ans : (B)
For photoelectric emission to take place the wavelength of incident
light must be less than
threshold value which is 5200 A∘
wavelength of IR light = 7800 A∘
wavelength of UV light = 4000 A∘
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Threshold wavelength for photoelectric emission from a metal surface is 5200 . Photoelectrons will be emitted when this surface is illuminated with monochromatic radiation froma)1 W IR lampb)50 W UV lampc)50 W IR lampd)10 W IR lampCorrect answer is option 'B'. Can you explain this answer?
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