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If an object is 30 cm away from a concave mirror of focal length 15 cm, the image will be
- a)erect
- b)virtual
- c)diminished
- d)of same size
Correct answer is option 'D'. Can you explain this answer?
Most Upvoted Answer
If an object is 30 cm away from a concave mirror of focal length 15 cm...
Explanation:
When an object is placed at a distance of 2f (twice the focal length) from a concave mirror, the image formed is of the same size as the object.
In this case, the object is placed at a distance of 30 cm from a concave mirror of focal length 15 cm. So, the distance between the object and the mirror is:
u = -30 cm (since the object is placed in front of the mirror)
f = -15 cm (since the mirror is concave)
Using the mirror formula:
1/f = 1/v + 1/u
1/-15 = 1/v + 1/-30
-2/30 = 1/v
v = -15 cm
So, the image is formed at a distance of 15 cm from the mirror. The magnification is given by:
m = -v/u
m = -15/-30
m = 1/2
Since the magnification is positive, the image formed is erect. And since the magnification is less than 1, the image formed is diminished.
However, since the object is placed at a distance of 2f from the mirror, the image formed is of the same size as the object. Therefore, option D is the correct answer.
When an object is placed at a distance of 2f (twice the focal length) from a concave mirror, the image formed is of the same size as the object.
In this case, the object is placed at a distance of 30 cm from a concave mirror of focal length 15 cm. So, the distance between the object and the mirror is:
u = -30 cm (since the object is placed in front of the mirror)
f = -15 cm (since the mirror is concave)
Using the mirror formula:
1/f = 1/v + 1/u
1/-15 = 1/v + 1/-30
-2/30 = 1/v
v = -15 cm
So, the image is formed at a distance of 15 cm from the mirror. The magnification is given by:
m = -v/u
m = -15/-30
m = 1/2
Since the magnification is positive, the image formed is erect. And since the magnification is less than 1, the image formed is diminished.
However, since the object is placed at a distance of 2f from the mirror, the image formed is of the same size as the object. Therefore, option D is the correct answer.
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Community Answer
If an object is 30 cm away from a concave mirror of focal length 15 cm...
Because as the focal length of concave mirror is 15cm then the radius of curvature becomes 30 cm and the object will on center of curvature by which image will form same on center of curvature which is inverted and of same length
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If an object is 30 cm away from a concave mirror of focal length 15 cm, the image will bea)erectb)virtualc)diminishedd)of same sizeCorrect answer is option 'D'. Can you explain this answer? for Class 12 2025 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about If an object is 30 cm away from a concave mirror of focal length 15 cm, the image will bea)erectb)virtualc)diminishedd)of same sizeCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 12 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If an object is 30 cm away from a concave mirror of focal length 15 cm, the image will bea)erectb)virtualc)diminishedd)of same sizeCorrect answer is option 'D'. Can you explain this answer?.
If an object is 30 cm away from a concave mirror of focal length 15 cm, the image will bea)erectb)virtualc)diminishedd)of same sizeCorrect answer is option 'D'. Can you explain this answer? for Class 12 2025 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about If an object is 30 cm away from a concave mirror of focal length 15 cm, the image will bea)erectb)virtualc)diminishedd)of same sizeCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 12 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If an object is 30 cm away from a concave mirror of focal length 15 cm, the image will bea)erectb)virtualc)diminishedd)of same sizeCorrect answer is option 'D'. Can you explain this answer?.
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