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Old May 6th 2010, 07:01 AM   #1
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Current electricity

Referring to the attached diagram, the reading of the voltmeter is 8V. The objective is to find the resistance of resistor R.

I assumed that the p.d. across the 160 ohm resistor = 8V, and used the method of potential dividers and found R to be 50 ohms.

However, the answer given was R= 38 ohms. Have I overlooked something here? Sorry if it seems like a nooby question.
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Old May 6th 2010, 12:34 PM   #2
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If two conditions are fulfiled:
1) The internal resistance of an ideal voltage source is zero
2) The internal resistance of the voltmeter is infinite
I get also 50 ohm.
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Old May 13th 2010, 02:12 AM   #3
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The flow of water in a river constitutes a current of water, flow of charge, i.e. charges in motion constitute an electric current. - The charged particles whose flow in a definite direction constitutes the electric current are called current carriers.e.g. electrons in conductors,ions in electrolytes,electrons and holes in semiconductors. The essential requirement for maintaining a steady current is a source of e.m.f. e.m.f. is associated with an arrangement or mechanism which can supply energy or does work to move the electric charge from lower potential energy to higher potential energy.
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