## Reflection: Unit Exams Electromagnetics Test & Motion Task - Section 3: Electromagnetics Test

The results of the test were very satisfying. The test was worth 44 points and the average score was around 37/44 with only 4 scores, out of 40, that were 25/44. Many students scored above 40 and several scored a perfect 44/44.

There were some common errors. One error that recurred was confusion about the size of numbers with negative exponents. In the image below, notice how the student was able to calculate the energies for two waves, given their frequencies, but then failed to identify the one whose energy was larger than 7.00 x 10 -19 joules (a supposed threshold of energy needed to disrupt cellular activity). This reveals a basic misunderstanding of the relative magnitudes of small numbers and the confusion around the use of scientific notation.

Another recurring issue was a difficulty with translating the information in a double slit problem into the correct variables. In this example, the student has mis-identified the values of "n," and "Yn," and "D" which, naturally, leads to an incorrect answer. Furthermore, after writing the wavelength correctly just above the problem, this student then transcribed it incorrectly when writing the equation. In retrospect, I was generous with taking just 2 points off this 5-point problem; perhaps I was more empathetic due to the confession: "Not sure I did this right."

Very few students fell into this category: total lack of preparation. Students had a mock quiz that was perfectly aligned with the actual test - a preview of the test, in essence. Furthermore, solutions ot the mock quiz were electronically available to students for two weeks before the test. Despite this support and opportunity, there were a few tests that looked like this:

I would still like this student to demonstrate some understanding of this material and will be offering a re-take. There will, however, be some sort of cap - perhaps no better than an 80% - to the score the second time around.

Unit Exams: Test Results

# Electromagnetics Test & Motion Task

Unit 5: Objects in Motion
Lesson 5 of 10

## Big Idea: We end our studies of electromagnetics and waves with a summative test.

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90 minutes

### Timothy Brennan

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