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A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image is
- a)virtual and at a distance of 16 cm from the mirror
- b)real and at a distance of 16 cm from the mirror
- c)virtual and at a distance of 20 cm from the mirror
- d)real and at a distance of 20 cm from the mirror
Correct answer is option 'B'. Can you explain this answer?
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Verified Answer
A biconvex lens of focal length 15 cm is in front of a plane mirror. T...
Focal length of the biconvex lens is 15 cm. A small object is placed at a distance of 30cm from the lens i.e. at a distance of 2f. Therefore the image should form at 30cm from the lens at I1.
But since the ray strike the plane mirror before reaching I1, the image I1 acts as the virtual object for reflection on plane mirror kept at a distance of 20 cm from it.
It should produce an image I2 but as the ray encounters the lens, it gets refracted and the final image is formed at I3. For the last refraction from the biconvex lens, u = 10 cm.
It should produce an image I2 but as the ray encounters the lens, it gets refracted and the final image is formed at I3. For the last refraction from the biconvex lens, u = 10 cm.
Applying lens formula 
Therefore a real image is formed at a distance of 16 cm from the plane mirror.
Most Upvoted Answer
A biconvex lens of focal length 15 cm is in front of a plane mirror. T...
Explanation:
Given,
- Focal length of biconvex lens, f = 15 cm
- Distance between the lens and the mirror, d = 10 cm
- Object distance, u = -30 cm (negative sign indicates that the object is placed in front of the lens)
To find: Image distance and nature of the image
Step 1: Find the position of the image formed by the lens.
Using the lens formula,
1/f = 1/v - 1/u
where, v is the image distance
Plugging in the values, we get
1/15 = 1/v + 1/(-30)
=> 1/v = 1/15 + 1/30
=> 1/v = (2+1)/30
=> v = 10 cm
So, the image formed by the lens is at a distance of 10 cm from the lens.
Step 2: Find the position of the final image formed by the mirror.
The image formed by the lens acts as an object for the mirror. The distance between the lens and the mirror is 10 cm, so the object distance for the mirror is 10 cm.
Using the mirror formula,
1/f = 1/v + 1/u
where, v is the image distance
Plugging in the values, we get
1/-10 = 1/v + 1/10
=> 1/v = -1/10 - 1/10
=> 1/v = -1/5
=> v = -5 cm
The negative sign of the image distance indicates that the image is formed behind the mirror.
Step 3: Find the nature of the final image formed by the mirror.
Since the image distance is negative, the image formed by the mirror is real. Also, the image distance is 5 cm, which is less than the focal length of the lens (15 cm). According to the lens formula, in this case, the image formed by the lens is real and inverted. Therefore, the final image formed by the mirror is real, inverted and at a distance of 20 cm from the mirror.
Hence, option B is the correct answer.
Given,
- Focal length of biconvex lens, f = 15 cm
- Distance between the lens and the mirror, d = 10 cm
- Object distance, u = -30 cm (negative sign indicates that the object is placed in front of the lens)
To find: Image distance and nature of the image
Step 1: Find the position of the image formed by the lens.
Using the lens formula,
1/f = 1/v - 1/u
where, v is the image distance
Plugging in the values, we get
1/15 = 1/v + 1/(-30)
=> 1/v = 1/15 + 1/30
=> 1/v = (2+1)/30
=> v = 10 cm
So, the image formed by the lens is at a distance of 10 cm from the lens.
Step 2: Find the position of the final image formed by the mirror.
The image formed by the lens acts as an object for the mirror. The distance between the lens and the mirror is 10 cm, so the object distance for the mirror is 10 cm.
Using the mirror formula,
1/f = 1/v + 1/u
where, v is the image distance
Plugging in the values, we get
1/-10 = 1/v + 1/10
=> 1/v = -1/10 - 1/10
=> 1/v = -1/5
=> v = -5 cm
The negative sign of the image distance indicates that the image is formed behind the mirror.
Step 3: Find the nature of the final image formed by the mirror.
Since the image distance is negative, the image formed by the mirror is real. Also, the image distance is 5 cm, which is less than the focal length of the lens (15 cm). According to the lens formula, in this case, the image formed by the lens is real and inverted. Therefore, the final image formed by the mirror is real, inverted and at a distance of 20 cm from the mirror.
Hence, option B is the correct answer.
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A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer?
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A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer?.
A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer?.
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A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image isa)virtual and at a distance of 16 cm from the mirrorb)real and at a distance of 16 cm from the mirrorc)virtual and at a distance of 20 cm from the mirrord)real and at a distance of 20 cm from the mirrorCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an
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