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प्रश्न
A pulse of light of duration 10-6 s is absorbed completely by a small object initially at rest. If the power of the pulse is 60 x 10-3 W, calculate the final momentum of the object.
उत्तर
Duration of the absorption of light pulse, t = 10-6s
Power of the pulse P = 60 x 10-3 W
Final momentum of the object, P = `"U"/"c"`
Velocity of light, C = 3 x 108
Energy U = power x time
Momentum, P = `(60 xx 10^-3 xx 10^-6)/(3 xx 10^8)`
P = 20 × 10-17 kg m s-1
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