STAR connection

StarConnection
Three batteries have their negative terminals connected together.
Find the voltage read by an ideal voltmeter.

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When the fuse blows

FUSEA fuse is a device to avoid the flow of a large current in a circuit. The potential difference across the fuse is negligible. In our circuit, the maximum current allowed through the fuse is 10 A. The light bulbs marked 40 Watt, 110 V. The bulbs connected to a voltage source of 110 V. What is the maximum number of bulbs that can be placed in parallel before the fuse blows?

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The light bulbs are connected in series or parallel

bulbsSerParTwo identical light bulbs are connected to identical batteries in two different ways. First they are connected in series and then in parallel. In which circuit will the bulbs shine brightly? What is the ratio of the power supplied in series to the power supplied in parallel?

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The resistance of each resistor

The total resistance of the circuit is 10 Ω. If the resistors R1 and R3 are swapped then the total resistance of the circuit will increase 100 times. If the resistors R2 and R3 are swapped then the total resistance of the circuit will increase by 0.2%.

3Resistors

Find the resistance of each resistor.

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The Ring

Ring2
 

A homogeneous wire is used to make a ring with a jumper on the diameter AB. What is the percentage change in the resistance between points A and B, if the jumper is cut?
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Which of the bulbs will fuse?

DC1Two electric bulbs marked 25W – 220V and 100W – 220V are connected in series to a 440V supply. Which of the bulbs will fuse?

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The greatest possible heating power.

wiresCoil

The four thin coiled wires have resistance of 10 ohms, 20 ohms, 30 ohms and 40 ohms. The battery has a voltage of 20 v and the internal resistance of 20 ohms. Please show how to make a heater with the greatest possible heating power.

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