NEET Exam > NEET Questions > A doctor advises a patient to use spectacles ...
Start Learning for Free
A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?
- a)-6.5 D
- b)-1.5 D
- c)6.5 D
- d)1.5 D
Correct answer is option 'B'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Most Upvoted Answer
A doctor advises a patient to use spectacles with a convex lens of foc...
Let the power of convex lens be P1.. P1=100/40=2.5 D P1=2.5D let the power of concave lens be P2.. P2= -100/25= -4D P2= -4D let combined the both values...we get; P1+P2=2.5-4= -1.5 D.
Free Test
FREE
| Start Free Test |
Community Answer
A doctor advises a patient to use spectacles with a convex lens of foc...
Given:
Focal length of convex lens, f1 = 40 cm
Focal length of concave lens, f2 = -25 cm (negative because concave lens has negative focal length)
To find:
Power of the combination of lenses
Solution:
The power of a lens is defined as the reciprocal of its focal length. The unit of power is dioptre (D), which is equal to the reciprocal of the focal length measured in meters.
1. Power of convex lens:
Power of convex lens P1 = 1/f1
P1 = 1/0.4 m (since f1 is given in cm, convert it to m)
P1 = 2.5 D
2. Power of concave lens:
Power of concave lens P2 = 1/f2
P2 = 1/-0.25 m (since f2 is given in cm, convert it to m and add negative sign)
P2 = -4 D
3. Power of combination of lenses:
When two lenses are placed in contact, their powers add up.
P = P1 + P2
P = 2.5 D - 4 D
P = -1.5 D
Therefore, the power of the combination of lenses is -1.5 D.
Option (B) is the correct answer.
Focal length of convex lens, f1 = 40 cm
Focal length of concave lens, f2 = -25 cm (negative because concave lens has negative focal length)
To find:
Power of the combination of lenses
Solution:
The power of a lens is defined as the reciprocal of its focal length. The unit of power is dioptre (D), which is equal to the reciprocal of the focal length measured in meters.
1. Power of convex lens:
Power of convex lens P1 = 1/f1
P1 = 1/0.4 m (since f1 is given in cm, convert it to m)
P1 = 2.5 D
2. Power of concave lens:
Power of concave lens P2 = 1/f2
P2 = 1/-0.25 m (since f2 is given in cm, convert it to m and add negative sign)
P2 = -4 D
3. Power of combination of lenses:
When two lenses are placed in contact, their powers add up.
P = P1 + P2
P = 2.5 D - 4 D
P = -1.5 D
Therefore, the power of the combination of lenses is -1.5 D.
Option (B) is the correct answer.
Attention NEET Students!
To make sure you are not studying endlessly, EduRev has designed NEET study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in NEET.
|
Explore Courses for NEET exam
|
|
Similar NEET Doubts
Top Courses for NEETView all
A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer?
Question Description
A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. 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 A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer?.
A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. 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 A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer?.
Solutions for A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for NEET.
Download more important topics, notes, lectures and mock test series for NEET Exam by signing up for free.
Here you can find the meaning of A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A doctor advises a patient to use spectacles with a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. What is the power of the combination ?a)-6.5 Db)-1.5 Dc)6.5 Dd)1.5 DCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice NEET tests.
|
|
Explore Courses for NEET exam
|
|
Suggested Free Tests
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup