Question

# Find the co-ordinates of image of point object P formed after two successive reflection at concave mirror and then at convex.

Open in App
Solution

## To find the co-ordinates of image of point object P formed after two successive reflection at concave mirror and then at convex.Solution:Consider concave mirror (M1) from figure, Object distance, u1=−20cmFocal length of the mirror, f1=−15cmApplying mirror formula, 1f1=1v1+1u1⟹1v1=1f1−1u1⟹1v1=1−15−1−20⟹1v1=−4+360⟹v1=−60cmMagnification, m1=−v1u1=−(−60)(−20)=−3 (image is inverted)The height at which the image point will be m1×AP=3×2=6mmThe image formed by concave mirror acts as object for convex mirror. Now, at convex mirror (M2) from figureObject distance, u2=+10cmFocal length of the mirror, f2=20cmApplying mirror formula, we get1f2=1v2+1u2⟹1v2=1f2−1u2⟹1v2=120−110⟹1v2=1−220⟹v2=−20cmHence the final position of image after two successive reflection at concave mirror and then at convex 20 cm in front of convex mirror, M2Magnification m2=−v2u2=−(−20)10=+2So the image of the point will be formed above, m2×C′P′=2×8=16mmSo the required coordinates of the image is, P(30,−14)

Suggest Corrections
0
Related Videos
Combination of Lenses and Mirrors
PHYSICS
Watch in App