Q.
An α− particle moves in a circular path of radius 0.83cm in the presence of a magnetic field of 0.25Wb/m2. The de Broglie wavelength associated with the particle will be
(Take h=6.63×10−34Js, e=1.6×10−19C)
7380
195
AIPMTAIPMT 2012Dual Nature of Radiation and Matter
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Solution:
Radius of the circular path of a charged particle in a magnetic field is given by R=Bqmv or mv=RBq
Here, R=0.83cm=0.83×10−2m B=0.25Wbm2 q=2e=2×1.6×10−19C ∴mv=(0.83×10−2)(0.25)(2×1.6×10−19)
de Broglie wavelength, λ=mvh=0.83×10−2×0.25×2×1.6×10−196.6×10−34 =0.01A˚