# Physics

The readings on a high resistance voltmeter, when a cell is connected across it, is 2.2 V . When the terminals of cell are also connected to a resistance of 5 ohm the voltmeter reading drops the 1.8 V. Calculate the internal resistance of cell

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1. cell voltage (no load) is 2.2v

cell voltage (5Ω load) is 1.8v

the internal resistance is in series with the cell voltage and the 5Ω load

the drop across the 5Ω load is .4v (2.2 - 1.8)
... so the circuit current is .08a (.4 / 5)

the internal resistance is ... (1.8 / .08)

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2. I = V/R = 1.8/5 = 0.36A = Circuit current.

Ri = (2.2-1.8)/0.36 = 0.4/0.36 = 1.11 Ohms = Internal resistance of cell.

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3. Look for the answer on what I gave you in physics

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