What is the max kinetic energy of photoelectrons from monochromatic beam?

In summary: The frequency of the light would be 1.2*10^15 Hz. In summary, the electric field associated with a monochromatic beam becomes zero 1.2*10^15 times per second and the maximum kinetic energy of the photoelectrons when this light falls on a metal surface is determined using the equation K(max)=hv-W, where W is the work function. The frequency of the light is 1.2*10^15 Hz.
  • #1
utkarshakash
Gold Member
854
13

Homework Statement


The electric field associated with a monochromatic beam becomes zero 1.2*10^15 times per second. Find the max kinetic energy of the photoelectrons when this light falls on a metal surface whose work function is 2.0 eV.

Homework Equations



The Attempt at a Solution


K(max)=hv-W where W=work function.
I have to find frequency from the given information which I don't know. But I guess it should be 1.2*10^15. Not sure about that.
 
Physics news on Phys.org
  • #2
utkarshakash said:

Homework Statement


The electric field associated with a monochromatic beam becomes zero 1.2*10^15 times per second. Find the max kinetic energy of the photoelectrons when this light falls on a metal surface whose work function is 2.0 eV.

Homework Equations



The Attempt at a Solution


K(max)=hv-W where W=work function.
I have to find frequency from the given information which I don't know. But I guess it should be 1.2*10^15. Not sure about that.

I believe your interpretation that ##f = 1.2 \times 10^{15} Hz## would be the case.

Convert your work function into Joules before you use it.

Your equation also seems to be a bit off, it should read:

##E_k = hf - W##
 
  • #3
Think about a sine function (or even better draw it).
How many times does it go through zero in a period?
It is easier to see if you take a period from a maximum to the next maximum in the sine wave.
 
  • #4
nasu said:
Think about a sine function (or even better draw it).
How many times does it go through zero in a period?
It is easier to see if you take a period from a maximum to the next maximum in the sine wave.

I got that. Thanks!
 
  • #5
Then what is the frequency of the light, in the problem?
Or you solved the question already?
 
  • #6
nasu said:
Then what is the frequency of the light, in the problem?
Or you solved the question already?

I solved that.
 

Related to What is the max kinetic energy of photoelectrons from monochromatic beam?

1. How do you find the maximum kinetic energy of an object?

The maximum kinetic energy of an object can be found using the formula: KEmax = 1/2 * m * v2, where m is the mass of the object and v is the velocity. This formula is derived from the basic equation for kinetic energy, which is KE = 1/2 * m * v2. By finding the velocity of the object and plugging it into the formula, you can calculate the maximum kinetic energy.

2. What is the significance of finding the maximum kinetic energy?

The maximum kinetic energy of an object is important because it represents the maximum amount of energy that the object possesses due to its motion. This energy can be used to do work or cause changes in the environment. Knowing the maximum kinetic energy can also help in understanding the behavior and capabilities of the object.

3. How does mass affect the maximum kinetic energy of an object?

The mass of an object directly affects its maximum kinetic energy. The greater the mass, the greater the maximum kinetic energy will be, assuming the velocity remains constant. This is because the formula for calculating kinetic energy involves mass, and a larger mass means more energy is required to move the object at a given velocity.

4. Can the maximum kinetic energy of an object be greater than its total energy?

No, the maximum kinetic energy of an object cannot be greater than its total energy. This is because kinetic energy is just one form of energy that an object can possess, and the total energy of an object takes into account all forms of energy including potential, thermal, and chemical. However, the maximum kinetic energy can be equal to the total energy of an object in certain scenarios.

5. How can the maximum kinetic energy of an object be measured experimentally?

The maximum kinetic energy of an object can be measured experimentally by using a device such as a dynamometer or a ballistic pendulum. These devices can measure the velocity of the object and use it to calculate the kinetic energy. Other methods may involve measuring the displacement of an object over time and using calculus to find its velocity and kinetic energy. Additionally, simulations and computer programs can also be used to calculate the maximum kinetic energy of an object.

Similar threads

Kinetic energy of a photoelectron
    • Introductory Physics Homework Help
Replies
2
Views
827
Resistance force changing the velocity of an object
    • Introductory Physics Homework Help
Replies
8
Views
262
Kinetic energy of the photoelectrons
    • Introductory Physics Homework Help
Replies
3
Views
2K
Photoelectric Effect Graph and Work Function Questions
    • Introductory Physics Homework Help
Replies
25
Views
3K
Photoelectric Effect: Find K.E. of Photoelectron in Air, Cs-137
    • Introductory Physics Homework Help
Replies
2
Views
1K
Photoelectric effect calculation
    • Introductory Physics Homework Help
Replies
8
Views
2K
Maximum Kinetic Energy of Photoelectrons from Irradiated Hydrogen Atoms
    • Introductory Physics Homework Help
Replies
2
Views
3K
Maximum kinetic energy / cutoff potential problem
    • Introductory Physics Homework Help
Replies
1
Views
2K
I Photoelectric effect and Saturation Current
    • Quantum Physics
Replies
12
Views
830
Use Max Planck's quantum theory to explain the following...
    • Introductory Physics Homework Help
Replies
4
Views
4K

Hot Threads

Recent Insights

Back
Top