How Is the Mass of a Charged Particle Determined in an Electric Field?

AI Thread Summary
To determine the mass of a positively charged particle suspended in an electric field, the relationship between force, charge, and electric field strength must be considered. The particle's charge is given as 9.35 pC, and the electric field is generated by two charged plates. The participant initially calculated the mass using the charge-to-proton mass ratio but arrived at an incorrect value. The correct approach involves equating the electric force (F = qE) to the gravitational force (F = mg), leading to the formula m = (q/g) * |E|. This method clarifies the calculation, resulting in the correct mass of 4.9 x 10^-4 kg.
adca14
Messages
11
Reaction score
0

Homework Statement


A positively charged particle (9.35pC) is suspended in equilibrium in an electric field between two horizontal parallel plates with opposite charges. Each one of the square plates has a charge of 5.5x10^-5C; and are separated by 6.25mm and their sides are 11cm long
what is the mass of the particle?

Homework Equations


E=kq/r^2
n=q/qp
idk...

The Attempt at a Solution


first i divided the charge of the particle by the elemental charge
9.35x10^-12/1.602x^-19
i got 58364544
then i multiplied this number by a protons mass
58364544*(1.673x^-27)
i got 9.764x10^-20

the book says the answer is 4.9x10^-4
soo confused!
 
Physics news on Phys.org
Consider the E-Field between the plates.

What does that come to?

You know that F = q*E

And you also know F = m*g

So ...

m = (q / g) * |E|
 
wow, i feel like a moron for not seeing that! thanks!
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Same Charge, Same Mass? | Subatomic Particles
Replies
28
Views
2K
The electric potential inside a conducting sphere with charge Q
Replies
11
Views
1K
Find net velocity of charged particle in electric field (symbols only)
Replies
14
Views
3K
Direction of electric field vector on the surface of charged conductor
Replies
9
Views
1K
Question about charged particle in an electric field
Replies
5
Views
2K
Sheet of charge - theory
Replies
1
Views
886
Electric Field for the circular path of a positively charged particle
Replies
3
Views
3K
I Thought I Understood Gauss' Law (Sheets)
Replies
26
Views
2K
Electric Potential slowing a charged particle to a stop
Replies
4
Views
3K
Two charged beads with a third bead in equilibrium
Replies
32
Views
3K

Hot Threads

Recent Insights

Back
Top