Help! Confused on Ray Diagram for Exam Question

In summary, the teacher marked the exam answer as correct, but the diagram the student drew looks like it could be for a diverging lens instead of a converging one. So the third picture is correct.
  • #1
Eveflutter
14
0
Fairly simple question I'd like someone to help with please. My teacher has me confused so I figured I'd turn to the forums for help.

1. Alright, so in an exam we had a ray diagram to draw. "Complete the ray diagram shown in Figure 6" they said (I sketched a replica * thumbs up* hongjinyoungreferenceimsorry):
image.jpg


Alrighty. (No relevant equations so I'm jumping to step three)3. I attempted it because, you know, it was an exam. I drew these emerging rays in yellow:

image.jpg


However, after the exam, I realized I drew it wrong? The lens seemed to be a diverging one so I sulked thinking that I'd get it wrong. I reattempted all the questions in the exam at home and I drew this for this particular question:
image.jpg

Since the lens seems to be divergent, the rays should diverge, no?

But no! I received my exam paper and my teacher marked the exam ray diagram correct and gave me the two marks that came with it.

So I'd really appreciate it if someone would deliver me from this time of confusion. Does that really represent a diverging lens so the third picture is correct? Or is it a converging lens so that the second picture is correct?
Thanks in advance!
 
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  • #2
I find it strange the symbols for the various lenses were not introduced before the exam. Did other students complain?
 
  • #3
mfig said:
I find it strange the symbols for the various lenses were not introduced before the exam. Did other students complain?
Its not that strange, honestly, it's just how it is. You see, my teacher rarely ever attends classes and when he does, he reaches sometimes twenty minutes before the bell rings and simply lectures us on life goals, the expectations of us, and talks about the country's state. He hardly teaches. It's up to us to either go to paid classes outside school or dive into our textbooks and learn everything there. We've complained so many times but they haven't done anything about it. We asked other teachers about it and they said that he does this to every class, every year. It's unfair.

I learn from my textbook. They mainly focused on converging lenses and showed us ray diagrams for them.
 
  • #4
mfig said:
I find it strange the symbols for the various lenses were not introduced before the exam. Did other students complain?
They drew the converging lenses like a ellipse-diamond mutant.
 
  • #5
I do not think that this is the place to post opinions of teachers.
The answers and explanations to physics questions have nothing to do with the competence of teachers either here or elsewhere.
Text books are a good source of exlanation.
 
  • #6
Eveflutter said:
So I'd really appreciate it if someone would deliver me from this time of confusion. Does that really represent a diverging lens so the third picture is correct?
Yes. Your exam answer should have been marked wrong.
 
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  • #7
haruspex said:
Yes. Your exam answer should have been marked wrong.
Thanks!
 
  • #8
lychette said:
I do not think that this is the place to post opinions of teachers.
The answers and explanations to physics questions have nothing to do with the competence of teachers either here or elsewhere.
Text books are a good source of exlanation.

"mfig" asked so I answered. But thanks, I'll keep you advice in mind for future threads. :ok:
And yeah, textbooks are great sources for explanations.
 

Related to Help! Confused on Ray Diagram for Exam Question

1. What is a ray diagram and why is it important?

A ray diagram is a visual representation of light rays and how they interact with different objects, such as lenses and mirrors. It is important because it helps us understand how light behaves and how it is affected by different materials.

2. How do I create a ray diagram for an exam question?

To create a ray diagram, you will need to first understand the properties of the object or material in question, such as its shape and refractive index. Then, use a ruler and a protractor to accurately draw the incident and refracted rays. Make sure to label all the important points and angles on your diagram.

3. What is the purpose of a ray diagram in an exam question?

The purpose of a ray diagram in an exam question is to test your understanding of the principles of light and optics. It helps demonstrate your ability to apply these principles to real-world scenarios and solve problems using the laws of reflection and refraction.

4. How do I know if my ray diagram is correct?

The best way to check if your ray diagram is correct is to compare it with a reference diagram or solution provided by your teacher or textbook. Make sure all the angles and distances are accurately represented and follow the laws of reflection and refraction.

5. What are some tips for drawing a clear and accurate ray diagram?

To draw a clear and accurate ray diagram, make sure to use a ruler and protractor to create straight and precise lines. Label all the important points and angles, and use different colors for incident and refracted rays. Additionally, practice drawing different types of ray diagrams to improve your skills.

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