In the context of a vernier calliper, an internal jaw is used to measure:

Question

In the context of a vernier calliper, an internal jaw is used to measure:

1. A. the depth of a beaker
2. B. the length correct up to 1 mm
3. C. the length of a rod and diameter of a sphere
4. D. the internal diameter of a hollow cylinder and pipes (Correct answer)

Correct Answer

Option D — the internal diameter of a hollow cylinder and pipes

Detailed Solution & Explanation

The correct answer is the internal diameter of a hollow cylinder and pipes.

Key Points

• The internal (upper) jaws of a vernier calliper measure inside dimensions such as the internal diameter of hollow cylinders and pipes.
• The external jaws measure outside dimensions, and the depth rod measures depth.

Additional Information

• A vernier calliper has three measuring parts: external jaws for outside dimensions, internal jaws for inside dimensions, and a depth rod for depth.
• Its least count is the main-scale division minus the vernier-scale division — typically 0.1 mm (0.01 cm) for a standard instrument.
• The vernier principle works because the vernier scale's divisions are slightly shorter than the main scale's, so exactly one pair of lines coincides.
• For finer work a screw gauge (micrometer) is used instead, with a least count of about 0.01 mm.