Unit notes and practice questions
Everything here is for unit 1 of the Grade 11 Physics textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.
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A short video lesson on this chapter, made by Temari. It loads only when you press play.
The scientific method, one step at a time · 4 min · 2 past exam questions worked through
Tap a part to play the lesson from there.
The cards filed under this chapter on the Grade 11 Physics page. Open one at a time.
When you use it
When asked to classify a statement as knowledge that comes from experience or knowledge that comes from reason, such as mathematics and logic.
Watch out
Mathematical truths such as 2+2=4 are a priori knowledge supplied by reason, even when an example with apples is used to illustrate them. Do not label them a posteriori just because the example uses real objects.
Drafted from Grade 11 Physics, pages 1-16, then checked twice before it went up
| Altitude (m) | Boiling point of water (°C) |
|---|---|
| 150 | 99.5 |
| 305 | 99 |
| 610 | 98 |
| 1524 | 95 |
When you use it
When a question gives or asks for the boiling point of water at a given height, or asks how altitude changes the boiling point.
Drafted from Grade 11 Physics, pages 1-16, then checked twice before it went up
10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.
Question 1
Which discovery was proved in 2016 by LIGO?
Answer: A Gravitational waves
Why
The chapter says Albert Einstein's idea about gravity as a wave was formulated in 1916 and was proved to be right in 2016 by LIGO. That idea is about gravitational waves.
Question 2
In which city is the Ethiopian Science and Art Museum located?
Answer: B Addis Ababa
Why
The chapter says the Ethiopian Science and Art Museum is situated in Addis Ababa. It was inaugurated by PM Abiy Ahmed on 4 October 2022.
Question 3
Which of these is not one of the four main ways of acquiring experiential knowledge?
Answer: D Mathematical and logical truths
Why
The four main ways of experiential knowledge are sensory perception, introspection, memory and testimony. Mathematics and logic are examples of non-experiential (a priori) knowledge, so they are not in this list.
Question 4
Which of these is a medical imaging method named in the chapter?
Answer: D Magnetic resonance imaging (MRI)
Why
The chapter lists computer tomography, magnetic resonance imaging, positron emission tomography, ultrasonic imaging and laser surgery as medical applications of physics. GPS, bar code scanners and semiconductors are everyday objects, not medical imaging methods.
Question 5
The table shows the boiling point of water at different altitudes. At 150 m, water boils at 99.5 °C. At 1524 m, water boils at 95 °C. By how many degrees Celsius is the boiling point lower at 1524 m than at 150 m?
Answer: B 4.5 °C
Why
Subtract the two boiling points: 99.5 °C minus 95 °C equals 4.5 °C. The boiling point is lower at the higher altitude, as the chapter's table shows.
Question 6
In the boiling water example, the student heated water at different altitudes and recorded the boiling temperature. Which step of the scientific method is this?
Answer: C Experiment
Why
The chapter lists the steps as observation, question, research, hypothesis, experiment, analysis and conclusion. Heating water at different altitudes and recording the results is the experiment step.
Question 7
Physicists in healthcare work alongside biomedical engineers. Which healthcare area is reserved for people with an additional medical degree?
Answer: A Cardiology
Why
The chapter says that cardiology and neurology are areas reserved for those with an additional medical degree. Physicists are regularly employed in radiology, radiation oncology and nuclear medicine.
Question 8
Which organization was established by Ethiopian physics professionals to enhance physics research and education in Ethiopia?
Answer: D Ethiopian Physical Society (EPS)
Why
The chapter says the Ethiopian Physical Society (EPS) was established by Ethiopian physics professionals to enhance physics research and education, which helps the country's overall development. EPSNA works with Ethiopians in Ethiopia and North America, and aaps is a student-run association.
Question 9
Albert Einstein's hypothesis about gravity as a wave was formulated in 1916. It was proved to be right in 2016. How many years passed between the hypothesis and the proof?
Answer: C 100 years
Why
Subtract the years: 2016 minus 1916 equals 100 years. The chapter says the proof took even more years, and it needed the work of thousands of scientists.
Question 10
As of 1 October 2022, there were 5,197 confirmed exoplanets in 3,833 planetary systems. About how many confirmed exoplanets were there per planetary system?
Answer: B 1.4
Why
Divide the number of exoplanets by the number of planetary systems: 5,197 divided by 3,833 is about 1.36, which is about 1.4. Option D is wrong because it divides by 1,000 and does not use the number of systems.
The app holds 12 questions on this unit, marked as you go. These are the first 10.
Unit 1 runs from page 1 to page 16 of the Ministry of Education edition.
Ministry of Education edition, English, 338 pages
Temari turns this chapter into timed practice and marks it as you go, with an AI tutor to explain anything that did not land.
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