Two resistors, each of 20 ohms, are connected in parallel and this combination is connected across a 40 V supply voltage.

Find the resistance in the circuit.

This question was previously asked in
RRB ALP Electronics Mechanic 21 Jan 2019 Official Paper (Shift 3)
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  1. 40 ohm
  2. 10 ohm
  3. 25 ohm
  4. 20 ohm

Answer (Detailed Solution Below)

Option 2 : 10 ohm
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Detailed Solution

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The correct answer is Option 2, i.e 10 ohm.

  • Given that two resistors of 20 ohms are connected in parallel.
  • So, the resultant resistance
  • 1/R= 1/R1 +1/R= 1/20 + 1/20 = 1/10 ohm
  • So, Rc = 10 ohm
  • A voltage source offers very minimal resistance. Hence, the total resistance is 10 ohms.

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