MCQOPTIONS
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| 1. |
Which of the following is not correct about wavelength standard? |
| A. | Wavelength of monochromatic light is an invariable unit of length |
| B. | Wavelength standard is a physical standard |
| C. | It is a reproducible standard |
| D. | It is a natural unit of length |
| Answer» C. It is a reproducible standard | |