Calculating the difference between two scale readings

Steps:

• Identify the main scale reading from the first measurement.
• Add the vernier scale contribution for the first reading.
• Repeat for the second measurement.
• Subtract the smaller value from the larger to find the difference.

Why B is correct:

• 11.84 mm matches the precise subtraction of the two vernier caliper readings, using the formula: difference = (MSR2 + VSR2 × LC) - (MSR1 + VSR1 × LC), where LC is least count.

Why the others are wrong:

• A ignores the vernier contribution, underestimating by 1.5 mm.
• C adds an extra 0.5 mm from misreading the main scale.
• D overestimates by including an incorrect alignment error of 1 mm.

Not enough information to verify exact readings without the figure. Final answer: B