Final answer:
To find the speed and number density of neutrons of energy 1.5MeV in a flux 7×10¹³/ (cm² s), you can use the formulas for speed and number density. The speed can be found by converting the energy to eV and solving an equation involving the energy and the rest mass of a neutron. Once the speed is known, it can be used to find the number density by dividing the flux by the speed.
Step-by-step explanation:
To find the speed and number density of neutrons of energy 1.5MeV in a flux of 7×10¹³/ (cm² s), you can use the formula:
Number density = Flux / speed
Let's assume the speed as v. So, the number density is given by:
Number density = 7×10¹³ / (v)
To find v, we need to convert the energy to eV and use the formula:
Energy = 1/2 * mass * v²
Given that the energy is 1.5MeV and the rest mass of a neutron is approximately 939.6 MeV/c², we can rearrange the formula to solve for v:
v = √(2 * Energy / mass)
Substituting the given values, we get:
v = √(2 * 1.5 * 10⁶ eV / (939.6 MeV/c²))
Calculating the value of v will give us the speed of the neutrons. We can then substitute this value into the number density formula to find the number density of neutrons.