How to Solve IGCSE Lens q with Unspecified Distance

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    Igcse Lens
In summary: My apologies.In summary, the conversation discusses the requirements for a sketch diagram in order to solve a question about the placement of an object in relation to a lens. The problem states that the width of the beam before it reaches the lens is 1.0 cm and the question is to find the distance(s) on the other side of the lens where the beam is less or more than 1.0 cm. The speaker also mentions the need to show some work or intention to answer the question. The conversation ends with a suggestion to draw a sketch and consider the given statement of the problem.
  • #1
S2100595
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Homework Statement
Could you please help me to figure out this question? The answer scheme says i) should be between 0 and 5.6 cm and ii) should be beyond 5.6 cm.
Relevant Equations
Not applicable
I know a sketch diagram is required for the question but they haven't specified the distance from the beam to the lens. They've just given the height of the beam. So how do I know how far I should place the object? Should the object (beam) be at infinity?
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  • #2
Read the problem. It clearly states that the width of the beam before it reaches the lens is 1.0 cm. So the question is to find the distance(s) on the other side of the lens where the beam is less or more than 1.0 cm. Should you require additional help, our rules require that you show some work or at least how you intend to answer this question.
 
  • #3
kuruman said:
Read the problem. It clearly states that the width of the beam before it reaches the lens is 1.0 cm. So the question is to find the distance(s) on the other side of the lens where the beam is less or more than 1.0 cm. Should you require additional help, our rules require that you show some work or at least how you intend to answer this question.
I have re-written how I intend to solve it
 
  • #4
S2100595 said:
I have re-written how I intend to solve it
Please don't edit your original post if you wish to reply. It could be confusing and is bad form. Start a new post. If you intend to draw a sketch, then draw one and post it. Mind the statement of the problem that says "A beam of parallel light strikes a converging lens of focal length 2.8 cm." What distance do you need to be given to draw a sketch of that?
 
  • #5
Alright never mind. This is my first post and I didn't realize there are so many restrictions and rules about how I can post on this forum.
 

1. How do I approach an IGCSE lens question with an unspecified distance?

When solving an IGCSE lens question with an unspecified distance, you need to use the lens formula: 1/f = 1/u + 1/v, where f is the focal length, u is the object distance, and v is the image distance. You will also need to use the magnification formula: M = v/u, where M is the magnification. These formulas will help you find the required values.

2. What is the first step in solving an IGCSE lens question with an unspecified distance?

The first step is to identify the given information and what is being asked. This will help you determine which formula to use and what values you need to find. It is important to carefully read the question and make note of any given values or information.

3. Can I use the same approach for all types of IGCSE lens questions with an unspecified distance?

Yes, the same approach can be used for all types of IGCSE lens questions with an unspecified distance. However, the values given and the formula used may differ depending on the specific question. It is important to carefully read the question and determine which formula to use.

4. How do I determine the sign conventions for an IGCSE lens question with an unspecified distance?

The sign conventions for an IGCSE lens question with an unspecified distance are the same as those for a lens question with a specified distance. A positive value for u indicates that the object is on the same side as the incident light, while a negative value indicates that the object is on the opposite side. A positive value for v indicates a real image, while a negative value indicates a virtual image.

5. What are some common mistakes to avoid when solving an IGCSE lens question with an unspecified distance?

One common mistake is forgetting to convert units. Make sure that all values are in the same unit before plugging them into the formulas. Another mistake is not carefully reading the question and missing important information. It is also important to double check your calculations and make sure you are using the correct formula. Lastly, be mindful of the sign conventions and make sure to use the correct signs for each value.

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