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The magnifying power of an astronomical ...

The magnifying power of an astronomical telescope is `5`. When it is set for normal adjustment, the distance between the two lenses is `24 cm`. Calculate the focal lengths of eye piece and objective lens.

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To solve the problem, we will follow these steps: ### Step 1: Understand the relationship between the focal lengths and magnifying power The magnifying power (M) of an astronomical telescope in normal adjustment is given by the formula: \[ M = \frac{F_O}{F_E} \] where \( F_O \) is the focal length of the objective lens and \( F_E \) is the focal length of the eyepiece. ### Step 2: Use the given magnifying power From the problem, we know that the magnifying power \( M = 5 \). Therefore, we can write: \[ \frac{F_O}{F_E} = 5 \] This implies: \[ F_O = 5 \times F_E \] ### Step 3: Use the distance between the lenses In normal adjustment, the distance between the two lenses is equal to the sum of their focal lengths: \[ F_O + F_E = 24 \, \text{cm} \] ### Step 4: Substitute \( F_O \) in the distance equation Now, substituting \( F_O \) from Step 2 into the distance equation: \[ 5F_E + F_E = 24 \] This simplifies to: \[ 6F_E = 24 \] ### Step 5: Solve for \( F_E \) Now, we can solve for \( F_E \): \[ F_E = \frac{24}{6} = 4 \, \text{cm} \] ### Step 6: Calculate \( F_O \) Now that we have \( F_E \), we can find \( F_O \): \[ F_O = 5 \times F_E = 5 \times 4 = 20 \, \text{cm} \] ### Final Result Thus, the focal lengths of the eyepiece and the objective lens are: - Focal length of the eyepiece \( F_E = 4 \, \text{cm} \) - Focal length of the objective \( F_O = 20 \, \text{cm} \) ---

To solve the problem, we will follow these steps: ### Step 1: Understand the relationship between the focal lengths and magnifying power The magnifying power (M) of an astronomical telescope in normal adjustment is given by the formula: \[ M = \frac{F_O}{F_E} \] where \( F_O \) is the focal length of the objective lens and \( F_E \) is the focal length of the eyepiece. ### Step 2: Use the given magnifying power ...
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PRADEEP-RAY OPTICS-Problem For Practice(d)
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