Question

Light travels with a speed of $3\times 10^{8}m/sec$. The distance travelled by light in 1 Femto sec is:

• A. 0.03 mm
• B. 0.003 mm
• C. 3 mm
• D. 0.0003 mm

Answer 1

Answer: (D)

$d=s\times t$

$=\left(3\times 10^{8}m/s\right)\left(10^{-15}s\right)$

$=3\times 10^{-7}m$

$=3\times 10^{-4}mm$

$=0.0003mm$