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When an astronomical telescope is focused on a distant star, the distance of the eye piece from the objective is 60 cm. When focused on a distant flag post the eye piece must be drawn at 0.1cm. If the focal length of the eye piece is 5cm; what will be the distance of the pole from the objective? Assume that the eye is focused for infinity?
  • a)
    302 m
  • b)
    300 m
  • c)
    30 m
  • d)
    303 m
Correct answer is option 'D'. Can you explain this answer?
Most Upvoted Answer
When an astronomical telescope is focused on a distant star, the dista...
Given data:
- Distance of the eye piece from the objective when focused on a star = 60 cm
- Distance of the eye piece from the objective when focused on a flag post = 0.1 cm
- Focal length of the eye piece = 5 cm

To find: Distance of the flag post from the objective

Formula used:
1/f = 1/v - 1/u
where f is the focal length of the eye piece, v is the distance of the final image from the eye piece and u is the distance of the object from the objective.

Calculation:

When focused on a distant star:

1/f = 1/v - 1/u

1/5 = 1/v - 1/60

Solving for v, we get:

v = 62.5 cm

When focused on a distant flag post:

1/f = 1/v - 1/u

1/5 = 1/v - 1/x

where x is the distance of the flag post from the objective.

We know that when focused on the flag post, the eye piece has to be drawn out to a distance of 0.1 cm. This means that the final image is formed at a distance of 0.1 cm from the eye piece.

So, v = 0.1 cm

Substituting the values of v and f in the above equation, we get:

1/5 = 1/0.1 - 1/x

Solving for x, we get:

x = 303.03 cm

Converting cm to m, we get:

x = 3.03 m

Therefore, the distance of the flag post from the objective is 303 m (approx).

Hence, the correct answer is option D.
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When an astronomical telescope is focused on a distant star, the dista...
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the distance of the pole from the objective
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When an astronomical telescope is focused on a distant star, the distance of the eye piece from the objective is 60 cm. When focused on a distant flag post the eye piece must be drawn at 0.1cm. If the focal length of the eye piece is 5cm; what will be the distance of the pole from the objective? Assume that the eye is focused for infinity?a)302 mb)300 mc)30 md)303 mCorrect answer is option 'D'. Can you explain this answer?
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When an astronomical telescope is focused on a distant star, the distance of the eye piece from the objective is 60 cm. When focused on a distant flag post the eye piece must be drawn at 0.1cm. If the focal length of the eye piece is 5cm; what will be the distance of the pole from the objective? Assume that the eye is focused for infinity?a)302 mb)300 mc)30 md)303 mCorrect answer is option 'D'. Can you explain this answer? for Class 12 2024 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about When an astronomical telescope is focused on a distant star, the distance of the eye piece from the objective is 60 cm. When focused on a distant flag post the eye piece must be drawn at 0.1cm. If the focal length of the eye piece is 5cm; what will be the distance of the pole from the objective? Assume that the eye is focused for infinity?a)302 mb)300 mc)30 md)303 mCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 12 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for When an astronomical telescope is focused on a distant star, the distance of the eye piece from the objective is 60 cm. When focused on a distant flag post the eye piece must be drawn at 0.1cm. If the focal length of the eye piece is 5cm; what will be the distance of the pole from the objective? Assume that the eye is focused for infinity?a)302 mb)300 mc)30 md)303 mCorrect answer is option 'D'. Can you explain this answer?.
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