Question

Which of the given instruments is least precise?

• A. A metre scale, with smallest division being ${\left(\frac{1}{10}\right)}^{th}$of a centimetre
  
• B. A micro-metre of least count $5\mu$m
  
• C. An inch tape, with smallest division being ${\left(\frac{1}{16}\right)}^{th}$ of an inch
  
• D. A Vernier caliper whose one main scale division is $1$ mm and $10$ divisions of Vernier scale coincide with $9$ divisions of main scale
  

Answer 1

The correct option is C An inch tape, with smallest division being ${\left(\frac{1}{16}\right)}^{th}$ of an inch


Answer (1)
Least count of inch tape $=\frac{2.54}{16}=0.158\text{cm}$
Least count of metre scale $=\frac{1}{10}=0.1\text{cm}$
Least count of Vernier calliper $=0.1$ mm
$\therefore$ Inch tape is least precise.