Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 202330 JanuaryMorning Shift
Exam
JEE Main
Year
2023
Date
30 January
Shift
Morning Shift
Subject
Physics
Chapter
Dual Nature of Matter

JEE Main 2023 · 30 January · Morning Shift · Physics · Dual Nature of Matter

A small object at rest, absorbs a light pulse of power 20mW and...

A small object at rest, absorbs a light pulse of power 20mW20mW and duration 300ns300ns. Assuming speed of light as 3×108ms−13 \times {10}^{8}m{s}^{- 1}. The momentum of the object becomes equal to :

Options

  1. A0.5×10−17kgms−10 . 5 \times {10}^{- 17}kgm{s}^{- 1}
  2. B2×10−17kgms−12 \times {10}^{- 17}kgm{s}^{- 1}
  3. C3×10−17kgms−13 \times {10}^{- 17}kgm{s}^{- 1}
  4. D1×10−17kgms−11 \times {10}^{- 17}kgm{s}^{- 1}

Correct answer

B. 2×10−17kgms−12 \times {10}^{- 17}kgm{s}^{- 1}

Step-by-step solution

Momentum p=Energy(E)Speedoflight(c)p = \dfrac{Energy\left(E\right)}{Speedoflight\left(c\right)}

=Power×timec= \dfrac{Power \times time}{c}

=(20×10−3W)(300×10−9s)3×108ms−1= \dfrac{\left(20 \times {10}^{- 3}W\right)\left(300 \times {10}^{- 9}s\right)}{3 \times {10}^{8}m{s}^{- 1}}

=2×10−17kgms−1= 2 \times {10}^{- 17}kgm{s}^{- 1}

As momentum is conserved, therefore momentum of object will be 2×10−17kgms−12 \times {10}^{- 17}kgm{s}^{- 1}.

Practice Dual Nature of Matter on Quantrex Academy →

More from Dual Nature of Matter

K_1 and K_2 be the maximum kinetic energies of photoelectrons emitted from a surface of a… JEE Main 2026The de Broglie wavelength for an electron accelerated through the potential difference of… JEE Main 2026Given below are two statements: one is labelled as Assertion (A) and the other is… JEE Main 2026An electron is travelling with a velocity v in free space and when it enters a medium… JEE Main 2026An electron of mass m is moving in an electric field E = -2E_0 i ( E_0 = constant > 0 )… JEE Main 2026Light source having wavelength 331 nm is used to generate photo-electrons whose stopping… JEE Main 2026Match the LIST-I with LIST-II List-I List-II A. Planck's constant I. ML^2T^ -2 B.… JEE Main 2026The de Broglie wavelength associated with an electron accelerated through a potential… JEE Main 2026 Full Dual Nature of Matter list All JEE Main PYQs