What is the net charge of a metal sphere after adding 7.0 x 10^13 electrons?

  • Thread starter Thread starter MD2000
  • Start date Start date
  • Tags Tags
    Electricity
AI Thread Summary
The discussion centers on calculating the net charge of a metal sphere initially charged at +5.0 µC after adding 7.0 x 10^13 electrons. Each electron has a charge of approximately -1.6022 x 10^-19 C, leading to a total charge of about -11.22 µC from the electrons. When this negative charge is added to the sphere's initial positive charge, the correct net charge is approximately -6.22 µC. Participants emphasize the importance of accounting for the negative charge of the electrons in the calculation. The conversation highlights the need for careful unit management and understanding charge polarity.
MD2000
Messages
38
Reaction score
0
A metal sphere has a charge of +5.0 µC. What is the net charge after 7.0 x 10^13 electrons have been placed on it?

What I tried was to convert the number of electrons to a charge by multiplying it by (1.6 x 10^-19)..and then adding that to the 5..from which I got 16.2..am I takin the right approach?
 
Physics news on Phys.org
The metal sphere has a +5 µC charge, which means a deficit of electrons.

Add to this 7.0 x 1013 electrons, each of which has a charge of -1.6022 x 10-19 C.

So the total charge of electrons is 7.0 x 1013 * -1.6022 x 10-19. Note that the electron charge is negative.
 
I'm not sure how you got 16.2. Did you take into account the charge of electrons (-)? Also, make sure to check the units of the metal sphere.

Aw, astronuc, beat me to it :wink:
 
Last edited:
Ahh..I completely forgot the negative..thanks astronuc
 
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

Calculating Charge of an Electron w/ the Millikan Oil Drop Experiment
Replies
12
Views
2K
Kinetic and potential energy of a particle attracted by charged sphere
Replies
6
Views
2K
What is the initial charge of the second object in Coulombs?
Replies
3
Views
2K
Determine the net charge of sphere C
Replies
2
Views
1K
What is the net charge after adding electrons?
Replies
4
Views
8K
Calculating how many surplus electrons on each sphere
Replies
1
Views
6K
What Is the Escape Speed of an Electron from a Charged Glass Sphere?
Replies
2
Views
9K
+ charged sphere and - charged sphere touch and separate
Replies
2
Views
4K
Charge rearrangement on conducting spheres
Replies
21
Views
4K
Homework help:A small plastic sphere with a mass of 2.60 X 10-15 kg
Replies
5
Views
4K

Hot Threads

Recent Insights

Back
Top