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Question
State the sign convention to measure the distances for a lens.
Solution
- Every distance is measured starting at the optical centre.
- The object should be positioned to the left of the lens. It measures the object's distance, i.e., u.
- f stands for the second focus, also known as the focal length, and v stands for the image distance.
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Distances measured with respect to the incoming ray's direction are recorded as positive, while those measured in its opposite direction are recorded as negative. That is, distances marked as +ve to the right and -ve to the left of the lens.
- +ve and -ve stand for height or length above the major axis, respectively.
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