Force Experienced by an Electron in an Electric Field

AI Thread Summary
An electron in an electric field of strength 300 N/C experiences a force calculated using the formula F = qE, where q is the charge of the electron (1.6 x 10^-19 C). The correct force is approximately 4.8 x 10^-17 N, indicating that the provided answer choices are incorrect. For a particle with a mass of 0.005 kg and a charge of +4.0 µC, the electric field strength needed to balance its weight is derived from E = mg/q, resulting in approximately 1.225 x 10^4 N/C, which also does not match the listed options. The discussion highlights confusion over the calculations and the accuracy of the provided questions. Accurate application of the formulas is essential for resolving these physics problems.
Soaring Crane
Messages
461
Reaction score
0
An electron is placed in an electric field of strength 300 N/C. What is the magnitude of the force the electron experiences?
1.6x10^13 N
2.4x10^13 N
3.2x10^14 N
4.8x10^14 N
6.4x10^14 N

A particle of mass 0.005 kg is given a charge of +4.0 µC and is placed in an electrical field that is directed antiparallel to the Earth's gravitational field. What is the field strength, expressed in N/C, if it balances the weight of the particle?
1.6 x10^6
2.4 x10^6
3.2 x10^6
4.4 x10^6
4.7 x10^6

Wen I tried to do these questions, I did not even come close to the figure in bold. I thought F = Eq or F = mg/q would be sufficient enough, but I guess not. Can anyone explain how to arrive at each answer?

Thanks.
 
Physics news on Phys.org
F = Eq is the correct equation to use for the first part, but all those answers listed are wrong.
q is the charge of an electron = 1.6 * 10^-19 C,
Just look at the exponents. You would have to have an E in the order of 10^33 N/C in order to come anywhere near those numbers. Are you sure you copied the question correctly?

For the second, I think you mean E = mg/q not F = mg/q. Again, all the choices are wrong? Where did you get these questions?
 
Soaring Crane said:
An electron is placed in an electric field of strength 300 N/C. What is the magnitude of the force the electron experiences?
1.6x10^13 N
2.4x10^13 N
3.2x10^14 N
4.8x10^14 N
6.4x10^14 N
None of these answers are even close to being right. The force is qE. If E is 300 and q is 1.6e-19 Coulomb, qE = 4.8e-17 N.

A particle of mass 0.005 kg is given a charge of +4.0 µC and is placed in an electrical field that is directed antiparallel to the Earth's gravitational field. What is the field strength, expressed in N/C, if it balances the weight of the particle?
1.6 x10^6
2.4 x10^6
3.2 x10^6
4.4 x10^6
4.7 x10^6
Again: F = qE, but in this case F also = mg, so qE = mg; E = mg/q

Plugging in the numbers, E = 5e-3*9.8/4e-6 = 1.225 e4 N/C Again none of the answers fit.

Where did you get these questions?

AM
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Determining the magnetic force on an electron
Replies
3
Views
2K
Finding magnitude of electrical field at specific point
Replies
1
Views
5K
Finding the angle of an electron striking a plate
Replies
3
Views
2K
Movement of electron in an electric field
Replies
10
Views
7K
An electron & a proton are each placed in an electric field
Replies
1
Views
3K
Two charges and electric field?
Replies
1
Views
6K
What Is the Net Electric Force and Field on Charge 1?
Replies
7
Views
2K
Calculating Electric Field Strength and Direction for a Negative Charge
Replies
4
Views
2K
What Is the Magnitude of the Electric Field Between Parallel Plates?
Replies
4
Views
2K
Determine the electron's velocity.
Replies
2
Views
7K

Hot Threads

Recent Insights

Back
Top