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**1. Homework Statement**

You are supplied with a 3V battery and a variable resistor of 30 ohms

http://img12.imageshack.us/img12/8329/currentv.png" [Broken]

a) Complete the above circuit diagram such that it's possible to obtain a PD between 0 and 3 V between 2 terminals.Mark the 2 terminals as A and B(the lines in grey in the figure are the connections I've made)

b) A high resistance voltmeter is now connected between A and B and if its reading is to be 2 V,what should be the resistance to the left and to the right of the setting point of the 30 ohm resistor

c)After adjusting the setting point corresponding to B,a bulb marked 2V,0.6A is connected between A and B,but the bulb won't light up.Explain why

d) It is possible to light the bulb in the normal way by adjusting the resistor.Calculate the approximate resistances to the left and to the right of the resistor after this adjustment is done

**2. Homework Equations**

[tex]\sum[/tex]E = [tex]\sum[/tex]IR

**3. The Attempt at a Solution**

b) E = I*30

I = 3/30 = 0.1 A

2 = I*R

2= 0.1R

R= 20 ohms

c)I can't figure out why the bulb doesn't work.When I tried to calculate the resistance of the bulb,I get

R'(of bulb)= 2/0.6 =3

^{1}/

_{3}ohms which is less than the 20 ohm resistance of the rheostat,so wouldn't most or even all of the current flow through the bulb?If so then why won't it light up?

d) Not sure I can do part d ,without understanding part c),so I hope someone can help.

Thank you.

**1. Homework Statement**

**2. Homework Equations**

**3. The Attempt at a Solution**

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