Question

which of the following micrometers can display a reading of 9.654 mm?
a) a micrometer graduated in thousandths of an inch
b) a micrometer graduated in hundredths of a millimeter with a vernier scale
c) a micrometer graduated in hundredths of a millimeter
d) a micrometer graduated in thousandths of an inch with a vernier scale

Explanation:

Step1: Analyze precision requirements

The reading is 9.654 mm. We need a micrometer with a precision of at least 0.001 mm.

Step2: Convert units and check options

1 inch = 25.4 mm. Thousandths of an inch is $\frac{1}{1000}\times25.4 = 0.0254$ mm precision. This is not precise enough for 9.654 mm reading. So options A and D are out.
Options C has a precision of hundredths of a millimeter (0.01 mm), not precise enough for 9.654 mm.
Option B has a micrometer graduated in hundredths of a millimeter (0.01 mm) with a vernier scale which can increase the precision to thousandths of a millimeter (0.001 mm).

Answer:

B. A micrometer graduated in hundredths of a millimeter with a vernier scale