RRB JE CBT-2 Electronics · 22 Apr 2025 · Shift 2 — General Science
RRB Junior Engineer (JE) · previous year paper
1 General Science questions from RRB JE CBT-2 Electronics · 22 Apr 2025 · Shift 2, with answers and Hindi and English explanations.
1.
एक अवतल लेंस की फोकस दूरी −2 cm है। इसकी क्षमता (पावर) कितनी है?
A concave lens has a focal length of −2 cm. What is its power?
- (A)−0.5 D
- (B)25 D
- (C)−50 D
- (D)0.5 D
Show answer and explanation
Answer: (C)
−50 D
क्षमता P = 1/f, जहाँ f मीटर में है। f = −2 cm = −0.02 m, अतः P = 1 ÷ (−0.02) = −50 D। अतः उत्तर −50 D है।
Power P = 1/f with f in metres. f = −2 cm = −0.02 m, so P = 1 ÷ (−0.02) = −50 D. So the answer is −50 D.
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