Practice Power Of A Lens (9.3.8) - Light – Reflection and Refraction

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8 questions

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6 sample questions

Question 1.
What is the formula for calculating the power of a lens?
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Think about what the letter 'f' represents.
Question 2.
Is the power of a concave lens positive or negative?
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Remember how concave lenses behave with light.
3Question 3.
What is the power of a lens with a focal length of 0.5 m?
- +2 D
- -2 D
- +0.5 D
- -0.5 D
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Use the formula P = 1 / f.
4Question 4.
A concave lens diverges light. Is its power positive or negative?
- True
- False
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Memorize that divergence indicates negative power.
Question 5.
If a lens has a power of -5 D, what is its focal length? How does this affect light rays?
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Recall the relationship between power and focal length.
Question 6.
An optician prescribes a lens with a power of +3 D. If a patient has a vision complaint requiring a 0.33 m focal length, will this lens be strong enough?
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Consider comparing focal lengths with the power measurement.

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