An object of height 1 cm is kept perpendicular to the principal axis o...
The distance between image and object is -\frac {40} {3}.
Given is the value of f as f = 10 cm and the u is u = 20 cm and will be taken negative as a case of convex lens.
Therefore the formula be used,
\frac {1} { f} = \frac {1} {u} + \frac {1} {v}
=>\frac {1} {10} = -\frac {1} {20} + \frac {1} {(- v)}
=>\frac {1} {10} = \frac {-1} {20} - \frac {1} {v}
=> \frac {1} {v} = -\frac {1} {20} - \frac {1} {10}
=> v = -\frac {20} {3}.
Therefore the distance between the object and image is,
2 v = 2 x -\frac {20} {3} = -\frac {40} {3}.
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An object of height 1 cm is kept perpendicular to the principal axis o...
Given data:
- Height of the object (h) = 1 cm
- Distance of the object from the mirror (u) = 20 cm
- Radius of curvature of the convex mirror (R) = 20 cm
Formula:
The magnification (m) of a convex mirror is given by the formula:
m = -v/u
Where,
- v is the distance of the image from the mirror
- u is the distance of the object from the mirror
Derivation:
1. The magnification (m) can also be given by the formula:
m = -h'/h
Where,
- h' is the height of the image formed
- h is the height of the object
2. For a convex mirror, the magnification (m) is always positive and less than 1. Therefore, we take the absolute value of the magnification.
3. Using the formula m = -v/u and substituting the given values, we have:
m = -v/20
4. Rearranging the formula, we get:
v = -20m
5. Substituting the value of h = 1 cm and h' = h*m in the formula m = -h'/h, we get:
m = -h'/h
-1/20 = -h'/1
h' = 1/20 cm
6. Using the formula m = -v/u, we can substitute the value of v and u:
-1/20 = -(-20m)/20
-1/20 = m
m = 1/20
Calculation:
1. We need to find the distance between the heads of the image and the object, which is the difference between the distances of the image and the object from the mirror.
2. Using the formula v = -20m, we can substitute the value of m:
v = -20 * (1/20)
v = -1 cm
3. The distance between the heads of the image and the object is given by:
Distance = |v - u|
Distance = |-1 - 20|
Distance = 21 cm
Final Answer:
The distance between the heads of the image and the object is 21 cm.
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