Science (086) — AI-generated practice question

(i) The ammeter has nearly zero resistance. When connected in parallel with the 10 Ω resistor, the parallel combination has an equivalent resistance ≈ 0 Ω.

Current through the ammeter branch:

$$I = \frac{V}{R} = \frac{6 \text{ V}}{0 \text{ Ω}} \approx \text{very large (extremely high) current}$$

Almost the entire current flows through the ammeter branch (short circuit).

(ii) This causes a short circuit — the circuit resistance drops nearly to zero, so an extremely large current flows from the cell. This can damage the ammeter, the cell, or cause overheating.

This connection is incorrect because an ammeter must be connected in series to measure current. In parallel, it bypasses the resistor (its near-zero resistance provides an easier path), so it neither measures the correct current through the resistor nor protects the circuit.

Source: Chapter 11, Section 11.6.2 – Resistors in Parallel

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• Examiners expect you to apply Ohm's law (I = V/R) with R ≈ 0 for the ammeter, giving a dangerously large current — the key concept is short circuit.
• You must state the correct usage (ammeter in series) to explain why parallel connection is wrong.
• Part (ii) carries the reasoning marks — mention both the effect (excessive current/short circuit) and the reason (near-zero resistance of ammeter bypasses the resistor).