Same chapter3 marksDifficulty: Medium
Where must an object be placed in front of a converging lens for the image to be virtual, erect and magnified? Name one use of this arrangement.
Refraction through a Lens
4 marksDifficulty: Hard
An object 3 cm tall is placed 15 cm from a converging lens of focal length 10 cm. Find the position, size and nature of the image.
Original Khojo Papers practice question — not from a past board paper.
Answer
The image is 30 cm from the lens, 6 cm tall, real and inverted.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
With u = −15 cm and f = +10 cm, 1/v = 1/10 − 1/15 = 1/30, so v = +30 cm. The magnification is 30/(−15) = −2, so the image is inverted and twice as tall, that is 6 cm.
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