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प्रश्न
A spherical mirror produces an image of magnification -1.0 on a screen placed at a distance of 30 cm from the pole of the mirror.
(i) Write the type of mirror in this case.
(ii) What is the focal length of the mirror ?
(iii) What is the nature of the image formed ?
(iv) Draw the ray diagram to show the image formation in this case.
उत्तर
Given :
m=-1 , v=-30 cm
We know that,
`m=-v/u`
`therefore -1=(30)/u`
`therefore u=-30`
(i) Since the magnification has a negative sign, the typa of mirror is a concave mirror
(ii) Using `1/f=1/v+1/u`, we get
`1/f=-1/30+(-1)/30`
`therefore 1/f=-2/30`
`therefore1/f=-1/15`
`=>f=-15` cm
∴ Focal length of the concave mirror is 15 cm
(iii) Since the magnitude of magnification is equal to 1 and the sign of magnification is negative, the image will be of the same size as the object, and its nature will be real and inverted.
(iv)
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संबंधित प्रश्न
Study the following diagram and select the correct statement about the device 'X' :
(A) Device 'X' is a concave mirror of radius of curvature 12 cm
(B) Device 'X' is a concave mirror of focal length 6 cm
(C) Device 'X' is a concave mirror of focal length 12 cm
(D) Device 'X' is a convex of mirror of focal length 12 cm
Draw the following diagram in your answer book and show the formation of image with the help of suitable rays:
At what distance from a concave mirror of focal length 10 cm should an object be placed so that:
its virtual image is formed 20 cm from the mirror?
Complete the following diagrams in figure by drawing the reflected rays for the incident rays 1 and 2 if F is the focus and C is the centre of curvature.
Draw a ray diagram to show the formation of the image of an object placed beyond the centre of curvature of a concave mirror. State the position, size and nature of the image.
A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see
(A) a very blurred image on the wall opposite to the mirror
(B) an erect and magnified image of the tree in the mirror
(C) no image as the screen has been removed
(D) a highly diminished inverted image of the tree at the focus of the mirror.
Study the following ray diagram and list two mistakes committed by the student while tracing it. Rectify these mistakes by drawing the correct ray diagram to show the real position and size of the image corresponding to the position of the object AB.
A concave mirror of radius 30 cm is placed in water. It’s focal length in air and water differ by ______.
The image formed by concave mirror is real, inverted and of the same size as that of the object. The position of object should be ______.
