The method and the results are on the electromagnetic induction lab. Do the analysis yourself first, then check the answers below.
Quick answer: Electromagnetic induction is the creation of an emf in a circuit when the magnetic flux linked with it changes. These answers go with the Physics 11-12 lab on electromagnetic induction: the graph, the calculations, the uncertainties and the conclusion explained, for all 6 analysis questions.
Here are the electromagnetic induction lab answers for physics grades 11-12: graph, calculations, uncertainties and conclusion. First do the lab yourself, then compare, and go back to the lesson if needed.
The sample data show emf rising in proportion to the speed of the magnet. The gradient has the unit volt second per metre. Your results may differ in size because they depend on your coil and magnet, but the proportionality should appear.
Level: Physics grades 11-12 (A Level · IB · Class 11-12) · Curriculum: IB D.4
Electromagnetic induction lab answers: the analysis explained
Question 1 Plotting
The points (0.99, 34), (1.40, 48), (1.98, 67), (2.43, 84), (2.80, 95) lie close to a straight line through the origin, so emf rises in step with speed.
Question 2 Pattern
The peak emf is directly proportional to the speed of the magnet.
Question 3 Gradient
gradient = ΣvE/Σv² = 34 mV per m/s, i.e. 0.034 V s/m.
Question 4 Explanation
Faster motion means the flux linked with the coil changes in a shorter time, so ΔΦ/Δt and the emf are larger. Emf is proportional to the rate of change of flux.
Question 5 Sign of the pulse
When the magnet enters, the flux through the coil increases; when it leaves, it decreases. The induced emf reverses direction, giving opposite signs. The second pulse is larger because the magnet is moving faster.
Question 6 Evaluation
Air resistance and eddy currents in the former reduce the speed; the tube may rub the magnet. Improve it by using timing gates to measure the actual speed at the coil.
