Solutions - CBSE Class 10 Sample Paper for 2022 Boards - Science [MCQ]

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Question 39 - Solutions - CBSE Class 10 Sample Paper for 2022 Boards - Science [MCQ] - Solutions to CBSE Sample Paper - Science Class 10

Last updated at July 18, 2026 by

If the power of a lens is - 4.0 D, then it means that the lens is aĀ 

(A) concave lens of focal length -50 mĀ 

(B) convex lens of focal length +50 cmĀ 

(C) concave lens of focal length -25 cmĀ 

(D) convex lens of focal length -25 mĀ 

Ā 

Answer -Ā 

If the power of a lens is - 4.0 D, then it means that lens is a [MCQ] - Solutions - CBSE Class 10 Sample Paper for 2022 Boards - Science [MCQ]

part 2 - Question 39 - Solutions - CBSE Class 10 Sample Paper for 2022 Boards - Science [MCQ] - Solutions to CBSE Sample Paper - Science Class 10 - Class 10

So, the correct answer is (c) Ā 

Ā 

Ā 

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Transcript

Question 39 If the power of a lens is āˆ’ 4.0 D, then it means that the lens is a (A) concave lens of focal length āˆ’50 m (B) convex lens of focal length +50 cm (C) concave lens of focal length āˆ’25 cm (D) convex lens of focal length āˆ’25 m Now, Power of lens = šŸ/š’‡ Here, focal length is in meter Since Power = āˆ’4D šŸ/š’‡ = āˆ’4 (āˆ’1)/š‘“ = f f = (āˆ’1)/4 m Converting in cm f = (āˆ’1)/4 Ɨ 100 cm f = āˆ’25 cm Since focal length is negative āˆ“ it is a concave lens So, the correct answer is (C)

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