Practice Combination of thin lenses in contact - 9.5.4 | 9. RAY OPTICS AND OPTICAL INSTRUMENTS | CBSE 12 Physics Part 2
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9.5.4 - Combination of thin lenses in contact

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Learning

Practice Questions

Test your understanding with targeted questions related to the topic.

Question 1

Easy

What is the formula for calculating the effective focal length of two lenses in contact?

💡 Hint: Think about the relationship between individual focal lengths.

Question 2

Easy

If Lens A has a focal length of 15 cm and Lens B has a focal length of 30 cm, what is the effective focal length?

💡 Hint: What happens when you find the common denominator?

Practice 4 more questions and get performance evaluation

Interactive Quizzes

Engage in quick quizzes to reinforce what you've learned and check your comprehension.

Question 1

What is the effective focal length for two lenses with focal lengths of 12 cm and 18 cm?

  • 7.2 cm
  • 27 cm
  • 27/5 cm

💡 Hint: Think about how focal lengths combine.

Question 2

True or False: The total magnification of a system of lenses is always less than the magnification of either lens alone.

  • True
  • False

💡 Hint: Consider how magnifications combine.

Solve and get performance evaluation

Challenge Problems

Push your limits with challenges.

Question 1

Consider two lenses placed in contact, one with a focal length of 5 cm and the other with a focal length of 20 cm. Calculate the effective focal length and total magnification if the first lens is used as a microscope objective.

💡 Hint: Use the effective focal length formula first, then the magnification concept.

Question 2

Design a simple optical system using three thin lenses in contact. Describe their purpose, effective focal length, and magnification characteristics.

💡 Hint: Consider what each lens contributes and how you adjust the calculations.

Challenge and get performance evaluation