CGPET 2017 Solved Paper

Given : λ=7×10−10m
Particle moves with a speed of

1

10

th.
So, velocity =

1

10

×3×108=3×107ms−1
∵λ=

h

mv

m=

h

λ.v

=

6.6×10−34J−s

7×10−10×3×107

m=0.3142×10−31kg
m=0.31×10−31 ≈10−31kg
Which is in accordance with mass of electron. Thus among the given particles, electron is the correct choice.