A small object at rest, absorbs a light pulse of power 20 mW and duration 300 ns. Assuming speed of light as 3 × 108 m / s, the momentum of the object becomes equal to :

Question

A small object at rest, absorbs a light pulse of power 20 mW and duration 300 ns. Assuming speed of light as 3 × 108 m / s, the momentum of the object becomes equal to : (A) 2 × 10-17 kg m / s (B) 1 × 10-17 kg m / s (C) 3 × 10-17 kg m / s (D) 0.5 × 10-17 kg m / s

Tardigrade Admin · Accepted Answer

text Momentum =( text Energy / C ) =( text Power × text time / C ) =((20 × 10-3 w )(300 × 10-9 s )/3 × 108 m / s ) =2 × 10-17 kg - m / s

Q. A small object at rest, absorbs a light pulse of power $20 mW$ and duration $300 n s$ . Assuming speed of light as $3 \times 1 0^{8} m / s$ , the momentum of the object becomes equal to :

$2 \times 1 0^{- 17} k g m / s$

$1 \times 1 0^{- 17} k g m / s$

$3 \times 1 0^{- 17} k g m / s$

$0.5 \times 1 0^{- 17} k g m / s$

$Momentum = \frac{Energy}{C}$
$= \frac{Power \times time}{C}$
$= \frac{( 20 \times 1 0 ^{- 3} w ) ( 300 \times 1 0 ^{- 9} s )}{3 \times 1 0 ^{8} m / s}$
$= 2 \times 1 0^{- 17} k g - m / s$

Q. A small object at rest, absorbs a light pulse of power 20mW and duration 300ns. Assuming speed of light as 3×108m/s, the momentum of the object becomes equal to :

2×10−17kgm/s

1×10−17kgm/s

3×10−17kgm/s

0.5×10−17kgm/s