Speed of electron when kinetic energy given

In summary, to solve for the speed of an electron when given a kinetic energy of 6.7*10^-19 Joules, you can use the classical kinetic energy equation by plugging in the mass of the electron and solving for v. However, if the kinetic energy is significantly larger, the relativistic kinetic energy equation may be necessary for a more accurate answer.
  • #1
gr3g1
71
0
Hey guys, my teacher saked us to solve for the speed of an electron when the kinetic energy is 6.7*10^-19 Joules

So, I fit in the mass of an electron, and the kinetic energy, and solve for v in the 1/2mv^2 equation??

Thanks a lot
 
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  • #2
gr3g1 said:
Hey guys, my teacher saked us to solve for the speed of an electron when the kinetic energy is 6.7*10^-19 Joules
So, I fit in the mass of an electron, and the kinetic energy, and solve for v in the 1/2mv^2 equation??
Thanks a lot

well obviously yes...thats one way of doing it!
 
  • #3
For that energy, the classical kinetic energy equation will work fine. If the energy were 100 times larger, you'd probably need to use the relativistic kinetic energy equation, unless your answer didn't have to be very accurate. If the energy were 1000 times larger, you'd definitely need the relativistic equation.
 

1. What is the relationship between the kinetic energy of an electron and its speed?

The kinetic energy of an electron is directly proportional to its speed. This means that as the kinetic energy increases, the speed of the electron also increases. Similarly, as the kinetic energy decreases, the speed of the electron decreases.

2. How is the speed of an electron calculated when its kinetic energy is given?

The speed of an electron can be calculated using the formula v = √(2KE/m), where v is the speed, KE is the kinetic energy, and m is the mass of the electron. This formula is derived from the classical equation for kinetic energy, KE = 1/2mv^2.

3. Can the speed of an electron exceed the speed of light when its kinetic energy is given?

No, according to the theory of relativity, the speed of light (c) is the maximum speed that any object can attain. Therefore, the speed of an electron cannot exceed the speed of light, regardless of its kinetic energy.

4. How does the speed of an electron change if its kinetic energy is doubled?

If the kinetic energy of an electron is doubled, its speed will also double. This is because the relationship between kinetic energy and speed is linear, meaning that any change in kinetic energy will result in an equal change in speed.

5. Is the speed of an electron affected by other factors besides its kinetic energy?

Yes, the speed of an electron can also be affected by external factors such as electric and magnetic fields. These fields can either accelerate or decelerate the electron, changing its speed even if its kinetic energy remains constant.

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