Question

Two thin Menses of Power + 3D and -5D are placed in
contact. Facal length of The combination will be

(i) -50cm (ii) -40cm (iii) -30cm (iv) -20cm​

Answer 1

Answer:

Convex mirror is always positive➕ Power,So it's focal length is always negative (because Centre of Curvature is inside the Mirror ----->( [Convex Mirror]

P =1/f

=> +1D = 1/f

+1D=1 Meter = 100 cm

F is negative (-) So, It's focal length is -100 cm

Explanation:

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