RRB Technician Grade 3 previous year question
A 2.0 cm tall object is placed 20 cm from a convex lens of focal length 15 cm. What is the magnification produced by the lens?
Asked in RRB Technician Grade 3 (10 Mar 2026 Shift 2) · Science
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Correct answer: (B) −3
Using the lens formula 1/v − 1/u = 1/f with u=−20 cm, f=+15 cm: 1/v = 1/15 − 1/20 = 1/60, so v=60 cm. Magnification m = v/u = 60/(−20) = −3.
हिंदी में प्रश्न
2.0 cm लंबे एक बिंब को 15 cm फोकस दूरी वाले उत्तल लेंस से 20 cm की दूरी पर रखा गया है। लेंस द्वारा उत्पन्न आवर्धन कितना है?
उत्तर जाँचने के लिए किसी विकल्प पर टैप करें।
उत्तर और व्याख्या देखें
सही उत्तर: (B) −3
लेंस सूत्र 1/v − 1/u = 1/f का उपयोग करने पर, u=−20 सेमी, f=+15 सेमी के साथ: 1/v = 1/60, अतः v=60 सेमी। आवर्धन m = v/u = 60/(−20) = −3 प्राप्त होता है।
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