What is the stopping potential when metal with work function?
Solution. When a metal with work function 0.6 eV is illuminated with light of energy 2 eV, the stopping potential will be 1.4 V.
Does stopping potential depends on metal?
Thus the stopping potential depends upon the frequency of the incident light and the material of the metal surface.
What is the formula of stopping potential?
Given: Stopping potential = Vs = 2 V, wavelength of incident light = λ = 160 nm = 160 x 10-9 m, Threshold wavelength = λo = 240 nm = 240 x 10-9 m, speed of light = c = 3 x 108 m/s, Planck’s constant = h = 6.63 x 10-34 Js, Charge on electron = e = 1.6 x 10-19 C.
How does work function affect stopping potential?
The maximum kinetic energy that the ejected electron has is given by subtracting the work function from the energy found in one photon of light. The stopping voltage is readily used to determine the kinetic energy that the electrons have as they are ejected from the metal plate.
What is the stopping potential when a metal surface with work function 1.2 eV is?
Answer : A. Solution : `eVs=E-W_(0)` `:.V_(s)=(E)/(e)-(W_(0))/(e)=(3e)/(e)-(1.2eV)/(e)=1.8V`
What is stopping potential?
Stopping potential is the minimum negative voltage applied to the anode to stop the photocurrent. The maximum kinetic energy of the electrons equal the stopping voltage, when measured in electron volt.
What is work function of a metal?
The work function of a photo metal is the minimum energy required to just liberate an electron from the metal surface. During the collision of the photons with the electrons, the electron absorbs the energy of the photon completely.
On what factors the value of stopping potential depends?
Stopping potential depends on frequency of incident light.
What is the work function of a metal?
How do you find the work function of a metal?
- We can use this information to experimentally determine the work function of a material. To begin, let us rearrange the maximum kinetic energy formula to solve for 𝑊 : 𝑊 = ℎ 𝑓 − 𝐸 .
- Now recall the electron kinetic energy equation, 𝑊 = ℎ 𝑓 − 𝐸 . m a x.
- Finally, we can make the substitution for frequency: 𝑊 = ℎ 𝑐 𝜆 − 𝐸 .
Why are metals preferred for electron emissions?
Answer: It is because the free electrons in the metals do not have enough energy to escape from metal. The free electrons, which try to escape from the metal, are pulled by positive electric force of atomic nucleus towards the metal. Hence, free electrons cannot escape from metal without sufficient energy.
What is the formula of work function?
Since work function does not depend on wavelength of incident light so it will be constant for both cases. Thus, W=λ2hc−eVs1.
Is work function same for all metals?
EXPLANATION: Work function solely depends on the material of the metal used. Different metals have electrons present at different energy levels, depending on which the work function varies.
Does stopping potential depend on cathode material?
Stopping potential for photoelectrons depends on both the frequency of the incident light and nature of the cathode material.
What affects stopping potential?
On increasing intensity, the value of saturated current increases, whereas the stopping potential remains unchanged. For a given intensity of radiation, the stopping potential depends on the frequency. Higher the frequency of incident light higher the value of stopping potential.
What is the formula for work function?
The Formula for Photoelectric Effect
| h | Planck’s constant. |
|---|---|
| \nu | Frequency of the incident photon. |
| W | Work function. |
| E | The maximum possible kinetic energy of the emitted electron. It will be \frac{1}{2} mv^{2}, for mass m and velocity v of the electron. |
Why are metals with low work function preferred as thermionic emitters?
Lower the work function of the metal, more easily will be the thermions emitted. Metals with low work function emit thermions at low temperature. Hence the metal with low work functions are preferred as thermionic emitters.
What is the work function for the metal?