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$(a)$ $A$ concave mirror produces a three times enlarged real image of an object placed at $10\, cm$ in front of it. Calculate the focal length of the mirror.
$(b)$ Show the formation of the image with the help of a ray diagram when an object is placed $6\, cm$ away from the pole of a convex mirror.
$(b)$ Show the formation of the image with the help of a ray diagram when an object is placed $6\, cm$ away from the pole of a convex mirror.
(N/A) Given: Magnification $m = -3$ (for a real image),Object distance $u = -10\, cm$. We need to find the focal length $f$.
Using the magnification formula: $m = -v/u$
$-3 = -v / (-10)$
$-3 = v / 10$
$v = -30\, cm$
Using the mirror formula: $1/f = 1/v + 1/u$
$1/f = 1/(-30) + 1/(-10)$
$1/f = (-1 - 3) / 30 = -4 / 30$
$f = -30 / 4 = -7.5\, cm$
Thus,the focal length of the concave mirror is $-7.5\, cm$.
$(b)$ The ray diagram for an object placed $6\, cm$ in front of a convex mirror is shown below.
Using the magnification formula: $m = -v/u$
$-3 = -v / (-10)$
$-3 = v / 10$
$v = -30\, cm$
Using the mirror formula: $1/f = 1/v + 1/u$
$1/f = 1/(-30) + 1/(-10)$
$1/f = (-1 - 3) / 30 = -4 / 30$
$f = -30 / 4 = -7.5\, cm$
Thus,the focal length of the concave mirror is $-7.5\, cm$.
$(b)$ The ray diagram for an object placed $6\, cm$ in front of a convex mirror is shown below.
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Similar Questions
One half of a convex lens of focal length $10\, cm$ is covered with a black paper. Can such a lens produce an image of a complete object placed at a distance of $30\, cm$ from the lens? Draw a ray diagram to justify your answer.
$A$ $4\, cm$ tall object is placed perpendicular to the principal axis of a convex lens of focal length $20\, cm$. The distance of the object from the lens is $15\, cm$. Find the nature,position and size of the image.
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Difficult
View Solution$(a)$ Define the optical centre of a spherical lens.
$(b)$ You are given a convex lens of focal length $30 \, cm$. Where would you place an object to get a real,inverted,and highly enlarged image of the object? Draw a ray diagram showing the image formation.
$(c)$ $A$ concave lens has a focal length of $20 \, cm$. At what distance from the lens should an object be placed so that it forms an image at $15 \, cm$ away from the lens?
$(b)$ You are given a convex lens of focal length $30 \, cm$. Where would you place an object to get a real,inverted,and highly enlarged image of the object? Draw a ray diagram showing the image formation.
$(c)$ $A$ concave lens has a focal length of $20 \, cm$. At what distance from the lens should an object be placed so that it forms an image at $15 \, cm$ away from the lens?
Difficult
View SolutionFor which type of mirror will the image always be erect,regardless of the distance at which the object is placed?
Easy
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Easy
View Solution$(i)$ Describe an activity to find the approximate value of the focal length of a concave mirror.
$(ii)$ What happens to the size of the image of an object when it is moved gradually away from a convex mirror?
$(iii)$ In an experiment to study refraction through a glass slab,it is observed that a ray of light undergoing refraction emerges parallel to the direction of the incident ray. Why does it happen so? Explain with the help of a diagram.
$(ii)$ What happens to the size of the image of an object when it is moved gradually away from a convex mirror?
$(iii)$ In an experiment to study refraction through a glass slab,it is observed that a ray of light undergoing refraction emerges parallel to the direction of the incident ray. Why does it happen so? Explain with the help of a diagram.
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