Multiple choice

Light travels with a speed of $3\times{10}^{8}$ {ms}^{-1}. The distance travelled by light in $1$ femto second is:

  1. $0.03mm$
  2. $0.003mm$
  3. $3mm$
  4. $0.0003mm$
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D Correct answer
Explanation

Distance = speed * time. Speed = 3 * 10^8 m/s. Time = 1 femtosecond = 10^-15 s. Distance = 3 * 10^8 * 10^-15 = 3 * 10^-7 meters. Converting to mm: (3 * 10^-7 m) * (1000 mm / 1 m) = 3 * 10^-4 mm = 0.0003 mm.

AI explanation

The distance travelled by light is calculated by the formula distance equals speed multiplied by time. Converting one femtosecond to seconds gives 10^-15 seconds, so the distance is (3 x 10^8) multiplied by 10^-15, which equals 3 x 10^-7 meters. Converting this to millimeters by multiplying by 1000 gives 3 x 10^-4 mm, which is 0.0003 mm.

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