In a Fresnel biprism experiment, the two positions of lens give separation between the slits as 16 cm and 9 cm respectively. What is the actual distance of separation?
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In a Fresnel biprism experiment, the two positions of lens give separation between the slits as 16 cm and 9 cm respectively. What is the actual distance of separation?

G1 Physics · Accepted Answer

Step 1: In Fresnel biprism lens-displacement method, image separations d₁, d₂ have product d². Step 2: Therefore true virtual-source separation d = √(d₁d₂). Step 3: d = √(16 × 9) = 12 cm. Final answer: (B) 12 cm.