Which of the following is the most precise device for measuring length
Which of the following is the most precise device for measuring length
- A
a vernier callipers with $20$ divisions on the sliding scale
- B
a screw gauge of pitch $1\,\, mm$ and $100$ divisions on the circular scale
- C
an optical instrument that can measure length to within a wavelength of light
- D
Precison can not be changed by changing the instrument.
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