Question

An ideal ammeter -

• A. should be connected in series and have high resistance.
• B. should be connected in parallel and have zero resistance.
• C. should be connected in series and have zero resistance.
• D. should be connected in parallel and have high resistance.

Hint:

Remember the ideal properties of basic meters:
- Ideal Ammeter: Connected in Series, Resistance = 0.
- Ideal Voltmeter: Connected in Parallel, Resistance = \(\infty\).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the proper circuit connection method and ideal internal resistance of an ammeter.

Step 2: Key Formula or Approach:
An ammeter is a device used to measure electric current. To measure the current flowing through a component, all of that current must pass through the ammeter.

Step 3: Detailed Explanation:

• To ensure that the entire current flowing through a circuit branch passes through the ammeter, the ammeter must be connected in series with that branch.

• Every electrical instrument has some internal resistance. If an ammeter has a significant resistance, connecting it in series would increase the total resistance of the circuit:
\[ R'_{total} = R_{circuit} + R_{ammeter} \]

• According to Ohm's law (\(I = V/R\)), this increase in resistance would decrease the current flowing through the circuit, resulting in an inaccurate, lower reading.

• To prevent the ammeter from altering the actual current it is designed to measure, its internal resistance must be as low as possible.

• For an ideal ammeter, this internal resistance is considered to be exactly zero.


Step 4: Final Answer:
An ideal ammeter should be connected in series and have zero resistance.