A plutonium- 239 nucleus initially at rest undergoes alpha decay to produce a uranium-235 nucleus. The uranium-235 nucleus has a mass of 3.90 x 10^-25 kg and moves away with a speed of 2.62 x 10^5 m/s. Determine the minimum wage electric potential difference that is required to bring the alpha particles to rest. This question is worth 12 marks and marks are awarded based in the two physics principles u choose from below and your final answer.
uniform motion
accelerated motion
circular motion
work energy 5heorem
conservation of momentum
conservation of mass energy
conservation of charge
conservation of nucleons
wave particle duality
So I was finding the velocity if the alpha particle using conservation of momentum and then using ek= vq to find stopping potential. However I can't see how this is worth 12 marks nor how it uses 2 of the concepts,
I would really appreciate some feedback on where I am wrong! Thanks
To determine the minimum wage electric potential difference required to bring the alpha particles to rest, we first need to calculate the velocity of the alpha particle before it undergoes alpha decay.
Conservation of momentum can be applied in this scenario. Since the plutonium-239 nucleus is initially at rest, the total momentum before alpha decay is zero. After alpha decay, the uranium-235 nucleus moves away with a speed of 2.62 x 10^5 m/s. To calculate the velocity of the alpha particle, we use the conservation of momentum equation:
(mass of uranium-235 nucleus) * (velocity of uranium-235 nucleus) = (mass of alpha particle) * (velocity of alpha particle)
Note that the mass of the alpha particle is given as 6.64 x 10^-27 kg.
Next, we can use the kinetic energy equation to find the stopping potential required. The kinetic energy of a particle is given by Ek = (1/2)mv^2, where Ek is the kinetic energy, m is the mass of the particle, and v is its velocity. In this case, the kinetic energy of the alpha particle needs to be equal to zero when it comes to rest.
Setting the kinetic energy equal to zero and using the derived velocity of the alpha particle, we can solve for the stopping potential.
Now, regarding the marking scheme, it states that marks will be awarded based on the two physics principles chosen and the final answer. To potentially score higher on this question, you may consider incorporating the principle of conservation of energy along with conservation of momentum.
By showing the steps involved in conservation of momentum and conservation of energy and arriving at the correct answer, you can demonstrate a strong understanding of these principles and potentially earn more marks.