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6. An experiment is set up to demonstrate a simple particle accelerator - Scottish Highers Physics - Question 6 - 2018
Question 6
6. An experiment is set up to demonstrate a simple particle accelerator. (a) Electrons are accelerated from rest between the cathode and the anode by a potential di... show full transcript
Worked Solution & Example Answer:6. An experiment is set up to demonstrate a simple particle accelerator - Scottish Highers Physics - Question 6 - 2018
Step 1
(a) (i) Show that the work done in accelerating an electron from rest is 2.6 × 10^-16 J.
Answer
The work done (W) on the electron can be calculated using the formula:
where:
- (charge of an electron)
Thus,
Calculating this gives:
This shows the work done in accelerating an electron from rest.
Step 2
(a) (ii) Calculate the speed of the electron as it reaches the anode.
Answer
The kinetic energy (K.E.) of the electron as it reaches the anode can be equated to the work done:
K.E. = rac{1}{2} mv^2
where:
- (mass of an electron)
- work done =
Setting them equal:
2.56 × 10^{-16} = rac{1}{2} (9.11 × 10^{-31}) v^2
Rearranging gives:
v^2 = rac{2(2.56 × 10^{-16})}{9.11 × 10^{-31}}
Calculating:
Step 3
(b) Suggest one change that is observed.
Answer
The screen will be brighter or increase glow with a greater potential difference (2.2 kV).
Justification: As the potential difference increases, electrons gain more energy and can either move faster or increase in number, leading to a brighter glow on the fluorescent screen.
Step 4
(c) Using your knowledge of physics comment on the model compared to a real particle accelerator.
Answer
The model accelerates a small ball using a motor which is quite basic compared to the highly advanced technology of a real particle accelerator like CERN's Large Hadron Collider (LHC). In a real accelerator, particles are accelerated to near-light speeds using electromagnetic fields in a vacuum, allowing for precise control and significant energy levels, which is key in high-energy physics experiments.
Compared to the model, a real accelerator can collide particles at immense speeds, leading to significant interactions that help in understanding fundamental particles and forces in the universe. In contrast, the model may only demonstrate basic principles without achieving the complex behaviors observed in real high-energy collisions.