The power of lens is 2.5D. What is the focal length and the type of lens
Answers
Explanation:
1. Power P = 1/f = 2.5D
Power P = 1/f = 2.5D f = 1/P = 100/2.5 = 40cm
Power P = 1/f = 2.5D f = 1/P = 100/2.5 = 40cmHere f = 40cm which is positive, it means the lens is a convex lens.
2. In case of a concave f is negative. So in the question f = -30cm
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.It means v = -3u.
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.It means v = -3u.Mirror formula = 1/f = 1/v + 1/u
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.It means v = -3u.Mirror formula = 1/f = 1/v + 1/u1/ (-30) = 1/(-3u) + 1/u
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.It means v = -3u.Mirror formula = 1/f = 1/v + 1/u1/ (-30) = 1/(-3u) + 1/u-1/30 = 1/u – 1/3u
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.It means v = -3u.Mirror formula = 1/f = 1/v + 1/u1/ (-30) = 1/(-3u) + 1/u-1/30 = 1/u – 1/3u-1/30 = 3/(3u)
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.It means v = -3u.Mirror formula = 1/f = 1/v + 1/u1/ (-30) = 1/(-3u) + 1/u-1/30 = 1/u – 1/3u-1/30 = 3/(3u)u = -20cms
2. In case of a concave f is negative. So in the question f = -30cmMagnification m = -v/u = 3.It means v = -3u.Mirror formula = 1/f = 1/v + 1/u1/ (-30) = 1/(-3u) + 1/u-1/30 = 1/u – 1/3u-1/30 = 3/(3u)u = -20cmsIt means the object is placed 20cms in front of the mirror. Since focal length is -30 cm ,it means the object is placed between focus and optical centre.
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Answer:
Explanation:
P=2.5D
F=1/P
F=1/2.5
F=10/25
F=0.4m
F=40m
Here f = 40cm which is positive, it means the lens is a convex lens.