Advertisements
Advertisements
प्रश्न
The focal length of a small concave mirror is 2.5 cm. In order to use this concave mirror as a dentist's mirror, the distance of tooth from the mirror should be:
(a) 2.5 cm
(b) 1.5 cm
(c) 4.5 cm
(d) 3.5 cm
उत्तर
1.5 cm
When an object is placed between the pole and the focus of a concave mirror, an enlarged image is formed.
APPEARS IN
संबंधित प्रश्न
Briefly describe how you would find the focal length of a concave mirror quickly but approximately
The image formed by a concave mirror is real, inverted and highly diminished (much smaller than the object). The object must be:
(a) between pole and focus
(b) at focus
(c) at the centre of curvature
(d) at infinity
A concave mirror has a focal length of 25 cm. At which of the following distance should a person hold his face from this concave mirror so that it may act as a shaving mirror?
(a) 45 cm
(b) 20 cm
(c) 25 cm
(d) 30 cm
Give reason for your choice.
What kind of mirror can have a focal length of, −20 cm?
A bright object 50 mm high stands on the axis of a concave mirror of focal length 100 mm and at a distance of 300 mm from the concave mirror. How big will the image be?
An object is placed at a large distance in front of a concave mirror of radius of curvature 40 cm. The image will be formed in front of the mirror at a distance:
(a) 20 cm
(b) 30 cm
(c) 40 cm
(d) 50 cm
Suppose you have three concave mirrors A, B and C of focal lengths 10 cm, 15 cm and 20 cm. For each concave mirror you perform the experiment of image formation for three values of object distance of 10 cm, 20 cm and 30 cm. Giving reason answer the following:
(a) For the three object distances, identify the mirror/mirrors which will form an image of magnification – 1.
(b) Out of the three mirrors identify the mirror which would be preferred to be used for shaving purposes/makeup.
(c) For the mirror B draw ray diagram for image formation for object distances 10 cm and 20 cm.
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.
In which of the following, the image of an object placed at infinity will be highly diminished and point sized?
An image formed by a lens is erect. Such an image could be formed by a
