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.
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
If the frequency of incident light falling on a photosensitive material is doubled, then the kinetic energy of the emitted photoelectron will be ______.
What is the photoelectric effect?
Can microwaves be used in the experiment on photoelectric effect?
Photocurrent recorded in the microammeter in an experimental setup of the photoelectric effect vanishes when the retarding potential is more than 0.8 V if the wavelength of incident radiation is 4950 Å. If the source of incident radiation is changed, the stopping potential turns out to be 1.2 V. Find the work function of the cathode material and the wavelength of the second source.
The electrons are emitted in the photoelectric effect from a metal surface.
With the help of a circuit diagram describing an experiment to study the photoelectric effect.
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 kinetic energy of the most energetic photoelectron emitted from a metal surface is doubled when the wavelength of the incident radiation is reduced from λ1 to λ2. The work function of the metal is ______
The maximum velocity of the photoelectron emitted by the metal surface is 'v '. Charge and mass of the photoelectron is denoted by 'e' and 'm' respectively. The stopping potential in volt is ______.
For photoelectric emission from certain metal, the cut-off frequency is v. If radiation of frequency 2v impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass) ____________.
When a light of wavelength 4000 Å falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, light of wavelength 6000 Å is sufficient for photo emission. The work functions of the two emitters are in the ratio of ____________.
The work function of a metal is 1.6 x 10-19 J. When the metal surface is illuminated by the light of wavelength 6400 Å, then the maximum kinetic energy of emitted photo-electrons will be (Planck's constant h = 6.4 x 10-34 Js) ____________.
The work function of a metallic surface is 5.01 eV. The photoelectrons are emitted when light of wavelength 2000 Å falls on it. The potential difference applied to stop the fastest photoelectrons is [h = 4.14 x 10-15 eV sec] ____________.
Photoelectrons emitted from a metallic surface are initially ____________.
A metal surface is illuminated by photons of energy 5 eV and 2.5 eV respectively. The ratio of their wavelengths is ____________.
When certain metal surface is illuminated with a light of wavelength A., the stopping potential is V, When the same surface is illuminated by light of wavelength 2λ, the stopping potential is `("V"/3)`. The threshold wavelength for the surface is ______.
Light of different frequencies, whose photons have energies 3 eV and 18 eV respectively, successively illuminate a metal of work function 2 eV. The ratio of the maximum speeds of the emitted electrons will be ______.
The photon of frequency vis incident on a metal surface whose threshold frequency is v0. The kinetic energy of the emitted photoelectrons will be ______.
When a photosensitive surface is irradiated by lights of wavelengths `lambda_1` and `lambda_2`, kinetic energies of emitted photoelectrons are E1 and E2 respectively. The work function of the photosensitive surface is ____________.
An electromagnetic wave of wavelength '`lambda`' is incident on a photosensitive surface of negligible work function. If the photoelectrons emitted from this surface have the de-Broglie wavelength '`lambda_1`' then ____________.
When the work function of a metal increases, maximum kinetic energy of emitted photoelectrons ____________.
The maximum kinetic energy of the photoelectrons ejected will be ______ eV when the light of wavelength 350 nm is incident on a cesium surface. The work function of cesium = 1.9 eV.
We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.
A point isotropic light source of power P = 12 watts is located on the axis of a circular mirror of radius R = 3 cm. If the distance of the source from the centre of the mirror is a = 39 cm and the reflection coefficient of the mirror is α = 0.70 then the force exerted by the light ray on the mirror is ______ × 10-10 N.
For a given photosensitive material and frequency (> threshold frequency) of incident radiation, the photoelectric current varies with the intensity of incident light as:
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 ______.
Define photoelectric work function of a metal.
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.
