WBJEE 2019 Physics Solved Paper

As we know that de-Broglie wavelength is given as λ=

h

p

=

h

mv

.....(i)
where,
h = Planck constant
p = momentum of particle
v = velocity of particle and
m = mass of the particle.
Eq. (i) can be written as,
where, KE = Kinetic energy of particle
Hence, λ∝‌

1

√m

Now, ‌

λ‌proton ‌

λ‌electron ‌

=√‌

m‌electron ‌

m‌proton ‌

Given, mass of proton, m‌proton ‌=2000m‌electron ‌
‌

λ‌proton ‌

λ‌electron ‌

=√‌

1

2000

‌

λ‌proton ‌

λ‌electron ‌

=‌

1

20√5

⇒λp=‌

λe

20√5