Thermal neutrons are neutrons that move at speeds comparable to those of air molecules at room temperature. these neutrons are most effective in initiating a nuclear chain reaction among 235u isotopes. calculate the wavelength (in nm) associated with a beam of neutrons moving at 7.20 102 m/s. (mass of a neutron = 1.675 x10-27 kg.)

5.494× 10^-10 m or 0.5494 nm or 5.94×10^-1 nm

Explanation:

Electromagnetic radiation involves the emission of radioactive particles. Infrared radiation(IR), Ultraviolet-visible radiation (uv-vis), gamma rays and x-rays are all part of electromagnetic radiation.

Using de-Broglie's equation(de-Broglie equation shows that wavelength is inversely proportional to mass and velocity).

That is, wavelength= h/mv (1)

Where h= plank's constant= 6.626×10^-34 J.seconds= 6.626×10^-34 Kg m^2/ s^2 , m= mass and v = velocity.

(Recall: 1 J= 1Kg m^2/s^2)

From the question the parameters given are;

Wavelength =? , mass of neutron= 1.675× 10^-27, v= 7.20102 m/s

Substitute the parameters into equation (1) above;

Wavelength= 6.626× 10^-34 kg m^2 per s^2÷ 1.675×10-27 kg × 10^2× 7.2 m per seconds

Wavelength= 6.626×10^-34 kg m^2/s^2 ÷ 1.206×10^-24 kgm/s

Wavelength= 5.494×10^-10

Wavelength = 0.5494 nm

Wavelength = 5.494 ×10^-1 nm.