Reading multi-range analogue ammeter scale

Steps:

• Identify the range selector position in the diagram, set to 200mA full scale.
• Locate the pointer on the arc scale, between 180mA and 200mA marks.
• Estimate the needle's position: approximately 95% across the scale from 0.
• Multiply fraction by full scale: 0.95 × 200mA = 190mA.

Why D is correct:

• Analogue meters use proportional scales; the pointer at 190mA mark on 200mA range directly indicates 190mA per the linear deflection law.

Why the others are wrong:

• A misreads on 100mA range, underestimating by half.
• B misreads on 200mA range, confusing minor ticks for 165mA.
• C overestimates interpolation, ignoring exact 190mA alignment.

Final answer: D