
A variation problem
The current flowing in an electrical circuit at a constant potential varies inversely as the resistance of the circuit. If the current is 25 amperes when the resistance is 4 ohms, what is the current when the resistance is 5 ohms?
What is the answer?


Hello,
The current I variates inversely as the resistance R.
This means that there exists k such as :
I=k/R > k=RI
For I=25, R=4.
And you want to know I' if R'=5.
So I'=k/R'=RI/R'=4*25/5=20

Quote:
Originally Posted by
mt_lapin Is the answer 20?
Yep :p