NEET Chemistry (general) MCQ Question
Which of the following statements regarding the definition of the metre is correct?
The metre is defined as the length of the path travelled by light in vacuum during 1/299 792 458 of a second.
The metre was originally defined as the distance between two marks on a platinum-iridium bar at 0°C.
The current definition of the metre is based on the wavelength of light emitted by a neon laser.
The metre has been redefined multiple times since its original definition in 1960.
Correct Answer
Detailed Explanation
The metre is defined as the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second, as stated in the NCERT context. The original definition involved a platinum-iridium bar, but the current standard is based on the speed of light.
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