Class 12 Exam > Class 12 Questions > Power of the lens is -40, its focal length is... Start Learning for Free
Power of the lens is -40, its focal length is
- a)4m
- b)-40m
- c)-0.25m
- d)-25m
Correct answer is option 'C'. Can you explain this answer?
Most Upvoted Answer
Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mC...
The power of a lens is the reciprocal of the focal length with measurement in metres. The unit is diopter.
It is given that the focal length of a convex lens is 10 cm = 0.1 m.
⇒ The power of the lens is 1/0.1= 10 diopter.
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Community Answer
Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mC...
Given data:
Power of the lens = -40
To find:
Focal length of the lens
Formula:
Power of the lens = 1/focal length
where,
Power of the lens = P
Focal length of the lens = f
Calculation:
Substituting the given values in the formula, we get
-40 = 1/f
f = -1/-40
f = 0.025 m or -25 cm
Therefore, the focal length of the lens is -25 cm.
Explanation:
A lens is a transparent material that refracts light and forms an image. The power of a lens is the ability of the lens to converge or diverge light. It is denoted by the letter P and is measured in diopters (D). The formula to calculate the power of a lens is given as P = 1/f, where f is the focal length of the lens in meters.
In this question, the power of the lens is given as -40 D. To find the focal length of the lens, we can use the above formula by substituting the given values. Solving the equation, we get the focal length of the lens as -25 cm or 0.025 m.
Negative sign in the focal length indicates that the lens is a diverging lens. A diverging lens is a lens that disperses light rays and forms a virtual image.
Power of the lens = -40
To find:
Focal length of the lens
Formula:
Power of the lens = 1/focal length
where,
Power of the lens = P
Focal length of the lens = f
Calculation:
Substituting the given values in the formula, we get
-40 = 1/f
f = -1/-40
f = 0.025 m or -25 cm
Therefore, the focal length of the lens is -25 cm.
Explanation:
A lens is a transparent material that refracts light and forms an image. The power of a lens is the ability of the lens to converge or diverge light. It is denoted by the letter P and is measured in diopters (D). The formula to calculate the power of a lens is given as P = 1/f, where f is the focal length of the lens in meters.
In this question, the power of the lens is given as -40 D. To find the focal length of the lens, we can use the above formula by substituting the given values. Solving the equation, we get the focal length of the lens as -25 cm or 0.025 m.
Negative sign in the focal length indicates that the lens is a diverging lens. A diverging lens is a lens that disperses light rays and forms a virtual image.
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Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mCorrect answer is option 'C'. Can you explain this answer? for Class 12 2026 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Class 12 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mCorrect answer is option 'C'. Can you explain this answer?.
Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mCorrect answer is option 'C'. Can you explain this answer? for Class 12 2026 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Class 12 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Power of the lens is -40, its focal length isa)4mb)-40mc)-0.25md)-25mCorrect answer is option 'C'. Can you explain this answer?.
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