Question

The ratio of de Broglie wavelengths associated with thermal neutrons at temperatures 127°C and 352°C is

• A. 5 : 3
• B. 3 : 2
• C. 3 : 4
• D. 3 : 5

Hint:

Remember that temperature in de Broglie wavelength equations must be in Kelvin.

Answer 1

The Correct Option is A

The de Broglie wavelength is given by: $$ \lambda = \frac{h}{\sqrt{2 m k T}} $$ where $h$ is Planck’s constant, $m$ is the mass of the particle, $k$ is Boltzmann’s constant, and $T$ is the temperature in Kelvin. The ratio of wavelengths depends on the square root of the inverse of the temperature ratio. Thus, the ratio of wavelengths at 127°C and 352°C is 5:3.