How Do You Calculate Charge in Parallel Capacitors?

[name_ask17]

Homework Statement

A 4.0-µF and an 7.0-µF capacitor are connected in parallel across a 25-V battery. Find
the total charge stored on the two capacitors.

Homework Equations

q=Cv

The Attempt at a Solution

i did the eqivalent capactiy*25 volts to get 275 C as the charge but that was marked incorrect- will you explain to me what i am doing wrong? thanks ahead for assistance

 

[gneill]

Watch your orders of magnitude. What are the given units of capacitance?

 

[name_ask17]

columb per volt and they give 4 and 7- but how do i fing thr charge using the equation above?

 

[gneill]

columb per volt and they give 4 and 7- but how do i fing thr charge using the equation above?

What is the total capacitance in Farads?

 

[name_ask17]

isnt it just 11??
but how does that lead me to charge?

 

[gneill]

isnt it just 11??
but how does that lead me to charge?

No, it's not "11". The 11 has units. What are the units that the capacitors were specified with in the problem statement?

Once you have the total capacitance expressed in the correct units, then you can use the method that you employed previously to find the charge (with the correct units!).

 

[name_ask17]

OH! ok thanks you because what i was doing was not converting it back to c

 

[name_ask17]

but THANKS, you really did help