Question

While measuring the length of the rod by vernier callipers, the reading on the main scale is 6.4 cm and the eight divisions on vernier is in line with marking on the main scale division. If the least count of callipers is 0.01 and zero error - 0.04 cm, the length of the rod is ________

• A. 6.52 cm
• B. 6.48 cm
• C. 6.44 cm
• D. 6.4 cm

Hint:

Subtracting a negative zero error effectively adds the magnitude.

Answer 1

The Correct Option is A

Step 1: Concept
Total Reading ($TR$) = $MSR$ + ($VSR \times LC$) - ($Zero~Error$).
Step 2: Analysis
- Main Scale Reading ($MSR$) = 6.4 cm. - Vernier Scale Reading ($VSR$) = 8. - Least Count ($LC$) = 0.01 cm. - Zero Error = $-0.04$ cm.
Step 3: Calculation
- Observed Reading = $6.4 + (8 \times 0.01) = 6.4 + 0.08 = 6.48$ cm. - True Length = Observed Reading - (Zero Error). - True Length = $6.48 - (-0.04) = 6.48 + 0.04 = 6.52$ cm.
Step 4: Conclusion
Hence, the length of the rod is 6.52 cm.
Final Answer:(A)