Draw a schematic diagram of an electric circuit consisting of battery of five 2V cells, a 20 Ω resistor, a 30 Ω resistor, a plug key, all connected in series. Calculate the value of current flowing through the 20 Ω resistor and the power consumed by the 30 Ω resistor.
The schematic diagram is shown below.
Current Flowing Through 20Ω resistor
⇒ 
Hence the current flowing is 0.5 Ampere.
Power consumed by the 30 Ω resistor
Power = Voltage × current.
Given Voltage = 10V; current = 0.5A
⇒ Power = 10 × 0.5 = 5W
Hence power consumed by 30 Ω resistor is 5W.
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