Advertisements
Advertisements
प्रश्न
The work function of a surface is 3.1 eV. A photon of frequency 1 × 1015 Hz. Is an incident on it. Calculate the incident wavelength is photoelectric emission occurs or not.
Advertisements
उत्तर
Given:
φ0 = 3.1 eV = 3.1 × 1.6 × 10−19 J
ν = 1 × 1015 Hz
To find:
- Incident wavelength (λ)
- Will photoelectric emission occur.
Formulae:
- `lambda_0 = "hc"/phi_0`
- `lambda = "c"/"v"`
Calculation:
Using formula (i),
`lambda_0 = (6.63 xx 10^-34 xx 3 xx 10^8)/(3.1 xx 1.6 xx 10^-19)`
= `(6.63 xx 3)/(3.1 xx 1.6) xx 10^-7`
= antilog {log 6.63 + log 3 − log 3.1 − log 1.6} × 10−7
= antilog {0.8215 + 0.4771 − 0.4914 − 0.2041} × 10−7
= antilog {0.6031} × 10−7
= 4.010 × 10−7 m
= 4010 Å
Using formula (ii),
`lambda = (3 xx 10^8)/(1 xx 10^15)`
= 3 × 10−7 m = 3000 Å
As λ < λ0, photoelectric mission will occur.
- Incident wavelength is 3000 Å
- Photoelectric emission will occur.
APPEARS IN
संबंधित प्रश्न
What is the photoelectric effect?
The threshold wavelength of tungsten is 2.76 x 10-5 cm.
(a) Explain why no photoelectrons are emitted when the wavelength is more than 2.76 x 10-5 cm.
(b) What will be the maximum kinetic energy of electrons ejected in each of the following cases
(i) if ultraviolet radiation of wavelength λ = 1.80 × 10-5 cm and
(ii) radiation of frequency 4 x 1015 Hz is made incident on the tungsten surface?
As the intensity of incident light increases ______
The maximum kinetic energy of the photoelectrons depends only on ______
Find the kinetic energy of the emitted electron, if in photoelectric effect energy of incident Photon is 4 eV and work function is 2.4 eV.
Explain the concept of the photoelectric effect.
The energy of the incident photon on the metal surface is 3 W and then 5 W, where W is the work function for that metal. The ratio of velocities of emitted photoelectrons is ______.
The ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) second to first energy level and (ii) highest energy level to second level is respectively.
If the maximum kinetic energy of emitted electrons in photoelectric effect is 3.2 × 10-19 J and the work-function for metal is 6.63 × 10-19 J, then stopping potential and threshold wavelength respectively are
[Planck's constant, h = 6.63 × 1034 J-s]
[Velocity of light, c = 3 × 108 `"m"/"s"`]
[Charge on electron= 1.6 × 10-19 C]
Photoelectrons emitted from a metallic surface are initially ____________.
In photoelectric experiment, if both the intensity and frequency of the incident light are doubled, then the saturation of photoelectric current ______.
An important spectral emission line has a wavelength of 21 cm. The corresponding photon energy is (h = 6.62 x 10-34 Js, c = 3 x 108 m/s) ____________.
In photoelectric effect, for a light of different intensities but of same frequency, the stopping potential for a given metal is ____________.
When light of wavelength 'λ' is incident on a photosensitive surface, the stopping potential is 'V'. When light of wavelength '3λ' is incident on the same surface, the stopping potential is `"V"/6`. Threshold wavelength for the surface is _______.
Photoelectrons are emitted from a photosensitive surface for the light of wavelengths λ1 = 360 nm and λ2 = 600 nm. What is the ratio of work functions for lights of wavelength 'λ1' to 'λ2'?
Which one of the following statements ts INCORRECT for stopping potential in photoelectric emission?
A light of wavelength '`lambda`' and intensity 'I' falls on photosensitive material. If 'N' photoelectrons are emitted, each with kinetic energy E, then ____________.
When a metal with work function 0.6 eV is illuminated with light of energy 2 eV, the stopping potential will be ____________.
Which one of the following graphs represents the variation of photoelectric current (i) with intensity (I) of the incident light?
The wavelength of light incident on a metal surface is reduced from 300 nm to 200 nm (both are less than threshold wavelength). What is the change in the stopping potential for photoelectrons emitted from the surface will be ______ V. (Take h = 6.6 × 10-34 J-s)
We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.
On a photosensitive material when frequency of incident radiation is increased by 30%, kinetic energy of emitted photoelectrons increases from 0.4 eV. The work function of the surface is ______.
Photoelectric emission is observed from a metallic surface for frequencies ν1 and ν2 of the incident light rays (ν1 > ν2). If the ratio of the maximum value of the kinetic energy of the photoelectrons emitted in the first case to that in the second case is 2 : K, then the threshold frequency of the metallic surface is ______.
Give Einstein's explanation of the photoelectric effect.
By increasing the voltage in an electron diffraction tube, the radius of the diffraction rings will ______.
The threshold frequency for a certain metal for photoelectric effect is 1.7 x 1015 Hz. When a light of frequency 2.2 x 1015 Hz is incident on the metal surface, the kinetic energy of the emitted photoelectrons is 3.3 x.10-19 J. Calculate Planck's constant.
Light of wavelength 'λ' falls on a metal having work function \[\frac {hc}{λ_0}\]. Photoelectric effect will take place only if (λ0 is the threshold wavelength) ______.
