Question

You are given four ammeters A, B, C and D having least counts mentioned below:

1) Ammeter A Least count 0.25 A

2) Ammeter B Least count 0.05 A

3) Ammeter C Least count 0.02 A

4) Ammeter D Least count 0.1 A

Which of the ammeters would you prefer to do experiments to find the equivalent resistance of two resistances in parallel?

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Answer 1

Ammeter A

Since the resistances are connected in parallel then the current would be more. Hence an ammeter with a larger least count would help us calculate this current

Answer 2

Answer:

An ammeter with a larger least count would help to measure the current through circuit, when the resistance is of smaller value.

Explanation:

• Given four ammeters with their least counts.
• Ammeter is used to measure the direct and alternating current passing through a circuit.
• Least count is the least measure that can be measured using a device.
• Given the resistors are connected in parallel, then the equivalent resistance is

                              $\frac{1}{R_{eq} }= \frac{1}{R_{1} }+\frac{1}{R_{2} }+...$

• Therefore, the equivalent resistance will be a minimum value.
• From Ohm's law, $V=IR$, it is clear that the current and resistance are inversely proportional to each other.
• Therefore, if resistance is of minimum value, then the current through the circuit should be more.
• Hence, an ammeter with a larger least count would help to measure the current through circuit.