Dual Nature of Matter

JEE Main level, single correct, medium

72 of 200

Question 72 of 200

A nucleus A,A, with a finite de-broglie wavelength λA,{\lambda }_{A}, undergoes spontaneous fission into two nuclei BB and CC of equal mass. BB flies in the same direction as that of A,A, while CC flies in the opposite direction with a velocity equal to half of that of B.B. The de-Broglie wavelengths λB{\lambda }_{B} and λC{\lambda }_{C} of B and C are respectively:

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Answer: (B) λA2,λA\dfrac{{\lambda }_{A}}{2},{\lambda }_{A}

hλA=hλB−hλC\dfrac{h}{{\lambda }_{A}}=\dfrac{h}{{\lambda }_{B}}-\dfrac{h}{{\lambda }_{C}} …(i)
Also
λC=2λB{\lambda }_{C}=2{\lambda }_{B} ...(ii)
From equation (i) & (ii),

1λA=1λB−12λB\dfrac{1}{{\lambda }_{A}}=\dfrac{1}{{\lambda }_{B}}-\dfrac{1}{2{\lambda }_{B}}
λB=λA2;λC=λA{\lambda }_{B}=\dfrac{{\lambda }_{A}}{2}; {\lambda }_{C}={\lambda }_{A}

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