# What is the wavelength of a beam of neutron having:⦁ An energy of 0.025 eV?⦁ An electron and photon each have wavelength of 2A°. what are their momentum and energy ? - Applied Physics 1

Numerical

What is the wavelength of a beam of neutron having:
⦁ An energy of 0.025 eV?
⦁ An electron and photon each have wavelength of 2A°. what are their momentum and energy ? mn = 1.676×10 -27 kg, h = 6.625×10 -34 J-sec.

#### Solution

Given Data :-energy of neutron =0.025eV.
To find :-wavelength of a beam.

Calculation :- λ=h/(√2meV)

=(6.626×10^(-34))/(√2×1.676×10^(-27) ×0.025×10^(-19) ×1.6)

=1.8095A°.

Hence wavelength is equal to=1.8095A°.

2. Given Data :- λ=2A°,mn =1.676×10-27  kg,h= 6.625× 10-34 J-sec.

To find :- momentum and energy.

Calculations :- λ =h/p ,………………….(for momentum)

2×10^(-10) = ( 6.625×10^(-34))/p

P=3.3125×10-24  kg-m/sec.

λ=h/(√2mE)

2×10^(-10)  = (6.625×10^(-34))/(√2×1.676×10^(-27) ×)

E = 5.721 × 10 -11 joules.
Hence momentum=3.3125×10-24 kg m/sec. and energy is=5.721×10-11 joules.

Concept: De Broglie Wavelength
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