# Physics

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A simple circuit is made of a power source, a rheostat and an ohmic resistor. The potential difference across the resistor is initially 5.0 +/- 0.1 V. A good lab student measures the current across the resistor to be 1.65 +/- 5 mA.

a)If the student increases the voltage across the resistor to 9.0 +/- 0.1 V, around what value should the measurement of the current across the resistor be (include uncertainties)?

b)what was the purpose of the rheostat in the circuit?

• Physics -

Are you sure the 1.65 +/- 5 mA is correct? That could be any value between 6.65 mA and -3.35 mA.

Did you mean 1.65 A +/- 5 mA ?

The rheostat in the circuit allows the current in the resistor to vary with a fixed-voltage power source (like a battery).

• Physics -

The problem says 1.65 (plus on top and the minus sign below it) 5 mA

I think the plus and minus is the uncertainties.

How would you be going about it doing both values....
I have no idea how to solve it and what the outcome is?

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