Advertisements
Advertisements
प्रश्न
The work function for a metal surface is 4.14 eV. The threshold wavelength for this metal surface is ______.
पर्याय
4125 Å
2062.5 Å
3000 Å
6000 Å
Advertisements
उत्तर
The work function for a metal surface is 4.14 eV. The threshold wavelength for this metal surface is 3000 Å.
Explanation:
w = 4.14 eV
l0 = ?
w = `"hc"/lambda_0`
`lambda_0 = "hc"/"w"`
`lambda_0 = (12,375)/("w"("ev"))` Å
`lambda_0 = (12,375)/4.14` Å
`lambda_0 = 2,985` Å
`lambda_0 ≈ 3,000` Å
APPEARS IN
संबंधित प्रश्न
Use the same formula you employ in (a) to obtain electron speed for an collector potential of 10 MV. Do you see what is wrong? In what way is the formula to be modified?
Can we find the mass of a photon by the definition p = mv?
Let nr and nb be the number of photons emitted by a red bulb and a blue bulb, respectively, of equal power in a given time.
A point source causes photoelectric effect from a small metal plate. Which of the following curves may represent the saturation photocurrent as a function of the distance between the source and the metal?
Calculate the number of photons emitted per second by a 10 W sodium vapour lamp. Assume that 60% of the consumed energy is converted into light. Wavelength of sodium light = 590 nm
(Use h = 6.63 × 10-34J-s = 4.14 × 10-15 eV-s, c = 3 × 108 m/s and me = 9.1 × 10-31kg)
A sphere of radius 1.00 cm is placed in the path of a parallel beam of light of large aperture. The intensity of the light is 0.5 W cm−2. If the sphere completely absorbs the radiation falling on it, Show that the force on the sphere due to the light falling on it is the same even if the sphere is not perfectly absorbing.
A small piece of cesium metal (φ = 1.9 eV) is kept at a distance of 20 cm from a large metal plate with a charge density of 1.0 × 10−9 C m−2 on the surface facing the cesium piece. A monochromatic light of wavelength 400 nm is incident on the cesium piece. Find the minimum and maximum kinetic energy of the photoelectrons reaching the large metal plate. Neglect any change in electric field due to the small piece of cesium present.
(Use h = 6.63 × 10-34J-s = 4.14 × 10-15 eV-s, c = 3 × 108 m/s and me = 9.1 × 10-31kg)
Two monochromatic beams A and B of equal intensity I, hit a screen. The number of photons hitting the screen by beam A is twice that by beam B. Then what inference can you make about their frequencies?
How would the stopping potential for a given photosensitive surface change if the intensity of incident radiation was decreased? Justify your answer.
The figure shows a plot of stopping potential (V0) versus `1/lambda`, where λ is the wavelength of the radiation causing photoelectric emission from a surface. The slope of the line is equal to ______.
