Potentiometer Problem: 3V Battery, 100cm Sliding Wire, and 60cm Voltmeter

[kaka01]

Homework Statement

A 3-V battery of internal resistance 1Ω is joined to a sliding wire of length 100 cm and resistance 5 Ω . A voltmeter , which takes negligible current , is connected across 60 cm length of the wire . (a) What is the reading of the voltmeter ? (b) If the reistance of the voltmeter were 150 Ω , then what would have been its reading ?

Homework Equations

I=E/(R+r)

The Attempt at a Solution

I=E/(R+r)

V=IR

V=0.5 x 5

=2.5

K=.025

Reading= .025x60=1.5 volt

I am not getting second part .
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[gneill]

What have you tried? Have you drawn the circuit? Can you post it?

 

[cnh1995]

Well split the wire into two parts (60 cm and 40 cm) and convert the circuit into lumped resistors..It'll get simple..