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The apparent depth of a needle lying at the bottom of the tank, which is filled with water of refractive index 1.33 to a height of 12.5cm is measured by a microscope to be 9.4cm. If water is replaced by a liquid of refractive index 1.63 upto the same height. What distance would the microscope have to be moved to focus on the needle again?
  • a)
    1.73 cm
  • b)
    2.13 cm
  • c)
    1.5 cm
  • d)
    2.9 cm
Correct answer is option 'A'. Can you explain this answer?
Verified Answer
The apparent depth of a needle lying at the bottom of the tank, which ...

Here, Real depth = 12.5cm and 

∴ Apparent depth = 12.5/1.63 = 7.67 cm
Now the microscope will have to shift from its initial position to focus 9.4 cm depth object to focus 7.67 cm depth object.
Shift distance = 9.4−7.67
= 1.73 cm
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Most Upvoted Answer
The apparent depth of a needle lying at the bottom of the tank, which ...
Given data:
- Refractive index of water = 1.33
- Height of water in the tank = 12.5 cm
- Apparent depth of the needle in water = 9.4 cm
- Refractive index of new liquid = 1.63

Calculating real depth of the needle in water:
- Using the formula for apparent depth in a liquid: Real depth = Apparent depth / Refractive index of the liquid
- Real depth of the needle in water = 9.4 cm / 1.33 = 7.07 cm

Calculating the distance the microscope needs to be moved:
- When the liquid is changed, the apparent depth changes but the real depth remains the same.
- Using the formula for apparent depth in a liquid: Apparent depth = Real depth x Refractive index of the liquid
- Apparent depth of the needle in the new liquid = 7.07 cm x 1.63 = 11.52 cm
- The microscope needs to be moved by the difference in apparent depths: 11.52 cm - 9.4 cm = 2.12 cm
Therefore, the distance the microscope needs to be moved to focus on the needle again is 2.12 cm (option A).
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The apparent depth of a needle lying at the bottom of the tank, which is filled with water of refractive index 1.33 to a height of 12.5cm is measured by a microscope to be 9.4cm. If water is replaced by a liquid of refractive index 1.63 upto the same height. What distance would the microscope have to be moved to focus on the needle again?a)1.73 cmb)2.13 cmc)1.5 cmd)2.9 cmCorrect answer is option 'A'. Can you explain this answer?
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The apparent depth of a needle lying at the bottom of the tank, which is filled with water of refractive index 1.33 to a height of 12.5cm is measured by a microscope to be 9.4cm. If water is replaced by a liquid of refractive index 1.63 upto the same height. What distance would the microscope have to be moved to focus on the needle again?a)1.73 cmb)2.13 cmc)1.5 cmd)2.9 cmCorrect answer is option 'A'. Can you explain this answer? for NEET 2024 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about The apparent depth of a needle lying at the bottom of the tank, which is filled with water of refractive index 1.33 to a height of 12.5cm is measured by a microscope to be 9.4cm. If water is replaced by a liquid of refractive index 1.63 upto the same height. What distance would the microscope have to be moved to focus on the needle again?a)1.73 cmb)2.13 cmc)1.5 cmd)2.9 cmCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The apparent depth of a needle lying at the bottom of the tank, which is filled with water of refractive index 1.33 to a height of 12.5cm is measured by a microscope to be 9.4cm. If water is replaced by a liquid of refractive index 1.63 upto the same height. What distance would the microscope have to be moved to focus on the needle again?a)1.73 cmb)2.13 cmc)1.5 cmd)2.9 cmCorrect answer is option 'A'. Can you explain this answer?.
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