How to Determine the Rate at Which a Battery Stores Chemical Energy?

[cyy91]

Homework Statement

a generator of e.m.f 20V and internal resistance of 0.5 ohm is used to charge a car battery of emf 12V and internal resistance 0.10 ohm.They are connected in series together with a resistance R whose value is adjusted to give a charging current of 2.0A.

I was asked to calculate
a) value of R
b) power of generator
c) total rate of dissipation of electrical energy
d) rate at which the battery stores chemical energy
e) efficiency of the whole operation

Homework Equations

P=VI
emf = I(R+r)

The Attempt at a Solution

i tried combining the 2 emfs and it sounds really funny, so i tried subtracting instead and still can't ring a bell.

How exactly can i calculate the rate at which a battery stores chemical energy?
anyone kindly provide me with an appropriate formula thanks.
better yet explain the whole question so i can answer other similar questions which caused me the same headaches...=S

 

[collinsmark]

Hello cyy91

i tried combining the 2 emfs and it sounds really funny, so i tried subtracting instead and still can't ring a bell.

As a first step, draw out the diagram for this configuration. Seeing the diagram visually might make this problem seem a little easier.

How exactly can i calculate the rate at which a battery stores chemical energy?

You need to calculate the power flowing into the battery's emf section (hint: it involves the battery's emf and the current flowing through it [albeit in the reverse direction as normal] ).

anyone kindly provide me with an appropriate formula thanks.
better yet explain the whole question so i can answer other similar questions which caused me the same headaches...=S

I think that once you start with the diagram, and work through what components are dissipating/using what power, things will fall into place.

 

[cyy91]

Hello cyy91



As a first step, draw out the diagram for this configuration. Seeing the diagram visually might make this problem seem a little easier.



You need to calculate the power flowing into the battery's emf section (hint: it involves the battery's emf and the current flowing through it [albeit in the reverse direction as normal] ).



I think that once you start with the diagram, and work through what components are dissipating/using what power, things will fall into place.

thx fr da help collinsmark...truly helps...