Question

In a circuit, the resistance, R ohms, is inversely proportional to the current, I amps. When the resistance is 12 ohms, the current in the circuit is 8 amps.
(a) find an equation connecting R and I
(b) Find the current when the resistance in the circuit is 6.4 ohms

Answer 1

Is this a physics or maths question? Do you have a voltage?

Answer 2

it's a maths question

Answer 3

and I don't have a voltage, no

Answer 4

Without a voltage I don't see how you can do better than:
I = 2/3(R)

Answer 5

okay, thank you

Answer 6

Do you see how I got there?
I simply took the ratio of resistance to current and inversed it as they're inversely proportionate, that gives 8/12 => 2/3 =)

Answer 7

so is that am equation connecting R and I?

Answer 8

Precisely, you can then use that to solve part b by plugging in your value for R. 6.3 ohms.

Answer 9

okay thats brilliant, thanks very much! :)

Answer 10

Sorry to be clear it should be:
\[I = \frac23 \frac1R\]

Answer 11

That's great, thank you for your help!