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NEET2009PhysicsRay OpticsActual

In a concave mirror, an object is placed at a distance d₁ from the focus and the image is formed at a distance d₂ from the focus. Then the focal length of the mirror is

Options

  1. Ad₁ d₂
  2. Bd₁ d₂
  3. C(d₁+d₂ ) / 2
  4. Dd₁ / d₂

Correct answer

A. d₁ d₂

Step-by-step solution

U sing 1 v + 1 u = 1 f Given u=f+d₁ v=f+d₂f= u v u+v = (f+d₁ ) (f+d₂ ) (f+d₁ )+ (f+d₂ ) On solving f= d₁ d₂

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