Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
What is the photoelectric effect?
Can microwaves be used in the experiment on photoelectric effect?
The electrons are emitted in the photoelectric effect from a metal surface.
Find the energy of photon which have momentum 2 × 10-16 gm-cm/sec.
Explain the concept of the photoelectric effect.
With the help of a circuit diagram describing an experiment to study the photoelectric effect.
The energy of a photon is 2 eV. Find its frequency and wavelength.
With the help of a circuit diagram describe the experiment to study the characteristics of the photoelectric effect. Hence discuss any 2 characteristics of the photoelectric effect.
The maximum velocity of photoelectron emitted is 4.8 m/s. If the e/m ratio of the electron is 1.76 × 1011 C/kg, then stopping potential is given by ______
Which one of the following is TRUE in photoelectric emission?
A metal surface is illuminated by light of given intensity and frequency to cause photoemission. If the intensity of illumination is reduced to one-fourth of its original value then the maximum KE of the emitted photoelectrons would be ______.
Threshold wavelength for lithium metal is 6250 Å. For photoemission, the wavelength of the incident light must be ______.
The threshold frequency for a certain photosensitive metal is v0. When it is illuminated by light of frequency v = 2v0, the maximum velocity of photoelectrons is v0. What will be the maximum velocity of the photoelectrons when the same metal is illuminated by light of frequency
v = 5v0?
In photoelectric effect, graph of saturation current versus frequency of light is plotted. The nature of the graph will be ____________.
When a metal with work function 0.6 eV is illuminated with light of energy 2 eV, the stopping potential will be ____________.
A metal surface having work function 'w0' emits photoelectrons when photons of energy 'E' are incident on it. The electron enters the uniform magnetic field (B) in perpendicular direction and moves in circular path of radius 'r'. Then 'r' is equal to (m and e be the mass and charge of electron respectively) ____________.
Is it always necessary to use red light to get a photoelectric effect?
The radiation corresponding to the 3 → 2 transition of a hydrogen atom falls on a gold surface to generate photoelectrons. These electrons are passed through a magnetic field of 5 × 10-4 T. Assume that the radius of the largest circular path followed by these electrons is 7 mm, and the work function of the metal is ______.
(Mass of electron = 9.1 × 10-31 kg)
When radiation of wavelength λ is used to illuminate a metallic surface, the stopping potential is V. When the same surface is illuminated with radiation of wavelength 3λ, the stopping potential is `"V"/4`. If the threshold wavelength for the metallic surface is nλ. then value of n will be ______.
Photoelectrons are observed to just emit out of a material surface when the light of 620 nm falls on it with the intensity of 100 W m-2. If the light of wavelength 400 nm is incident on the same material with an intensity of 1 W m-2, what would be the minimum reverse potential needed to stop the outflow of the electrons?
We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.
Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is ______.
In a photocell, frequency of incident radiation is increased by keeping other factors constant (v > v0), the stopping potential ______.
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 ______.
The photoelectric threshold for a certain metal surface is 3600 Å. If the metal surface is irradiated by a wavelength of 1100 Å, then kinetic energy of the emitted photoelectrons is ______.
When monochromatic light of frequency v1 falls on a metal surface, the stopping potential required is found to be V1. If the radiation of frequency v2 is incident on the surface, the stopping potential required V2 is ______. (v2 > v1)
Give Einstein's explanation of the photoelectric effect.
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) ______.
According to Einstein's photoelectric equation, the graph of kinetic energy of the photoelectron emitted from the metal versus the frequency of incident radiation gives a straight line graph whose slopе ______.
