In an electrical circuit, the ammeter reading decreases to _______ when the length of the wire is doubled.

The correct answer is one-half.

Key Points

• Resistance Relationship: The resistance of a wire is directly proportional to its length. Doubling the length of the wire doubles its resistance.
• Current and Resistance: According to Ohm’s Law, for a constant voltage, if resistance doubles, the current is halved.
• Practical Impact: In a practical circuit, this means that if you double the length of the wire, the increased resistance will result in less current flowing through the circuit.
• Ammeter Impact: Since the current is halved, the ammeter reading will show a value that is half of the original reading before the wire was lengthened.

Additional Information

Before Doubling Length:

   +----[R]----+
   |           |
  [V]         [A]
   |           |
   +-----------+

After Doubling Length:

   +----[2R]----+
   |            |
  [V]          [A']
   |            |
   +------------+

• Increased Distance: The distance between the voltage source (V) and the component (A) has been doubled.
• Circuit Path: The path connecting the voltage source to the component and resistor is longer.
• Component Placement: The resistor (R) remains in the same position relative to the voltage source and the other component, but the overall length of the connecting path is increased.
• Potential Effects:
  • Resistance: Longer lengths can lead to increased resistance in real-world applications due to the longer conductor path.
  • Signal Delay: In high-frequency circuits, doubling the length can affect signal propagation times

Important Points