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प्रश्न
Solve the following example.
5 cm high object is placed at a distance of 25 cm from a converging lens of focal length of 10 cm. Determine the position, size and type of the image.
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उत्तर
Given:
Height of object, ho = 5 cm
Object distance, u = -25 cm
Since the lens is converging, thus it is a convex lens.
Focal length of the lens, f = 10 cm
Using lens formula,
\[\frac{1}{v} - \frac{1}{u} = \frac{1}{f}\]
\[ \Rightarrow \frac{1}{v} = \frac{1}{10} + \frac{1}{- 25} = \frac{3}{50}\]
\[ \Rightarrow v = \frac{50}{3} = 16 . 7 cm\]
Thus, the image is formed
16 . 7 cm right of the lens.
Now, we know
\[\frac{v}{u} = \frac{h_i}{h_o}\]
\[ \Rightarrow h_i = \frac{50}{3 \times - 25} \times 5 = -\frac{10}{3} = - 3 . 3 \text{cm}\]
Thus, the size of the image is 3.3 cm. Negative sign shows that the image formed is real and inverted. Hence, the image formed is real and inverted and diminished.
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संबंधित प्रश्न
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(C) 20 cm on the other side of the lens and is of the same size, real and inverted.
(D) 20 cm on the other side of the lens and is of the same size, virtual and erect.
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Image distance (cm) |
| 1 | 60 | 15 |
| 2 | 48 | 16 |
| 3 | 36 | 21 |
| 4 | 24 | 24 |
| 5 | 18 | 36 |
| 6 | 16 | 48 |
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