internal resistance calculation

Answers:
a. 1.5V
b. V=Ir and V=1.5-1.2, r=1 ohms

I can't understand the answer to b. Here's what I did:
ℰE=V+Ir
r=(E-V)/I
with V=1.5-1.2, V=0.3V
r=(1.5-0.3)/0.3
r=4 Ohms

WHY doesn't this work?

THANKS

(edited 10 years ago)

Reply 1

natninja

21

Original post by krisshP

Answers:
a. 1.5V
b. V=Ir and V=1.5-1.2, r=1 ohms

I can't understand the answer to b. Here's what I did:
ℰE=V+Ir
r=(E-V)/I
with V=1.5-1.2, V=0.3V
r=(1.5-0.3)/0.3
r=4 Ohms

WHY doesn't this work?

THANKS

so from R=V/I we have the current through the cell of 0.3A and the voltage 'used up' overcoming the internal resistance as E-V=0.3V

so R=0.3/0.3=1

you've tried to use a formula that would only be valid for the whole circuit...

Reply 2

krisshP

OP

14

Original post by natninja

so from R=V/I we have the current through the cell of 0.3A and the voltage 'used up' overcoming the internal resistance as E-V=0.3V

so R=0.3/0.3=1

you've tried to use a formula that would only be valid for the whole circuit...

Thanks

internal resistance calculation

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you