Advertisements
Advertisements
प्रश्न
A student determines the focal length of a device 'X' by focusing the image of a distant object on a screen placed 20 cm from the device on the same side as the object. The device 'X' is
(a) Concave lens of focal length 10 cm
(b) Convex lens of focal length 20 cm
(c) Concave mirror of focal length 10 cm
(d) Concave mirror of focal length 20 cm
उत्तर
In case of concave mirror, the image will be formed on the same side on the screen at its focus point when object is distant.
Hence, the correct answer is option (d).
APPEARS IN
संबंधित प्रश्न
With the help of an appropriate ray diagram, state the sign conventions for reflection by a spherical mirror.
The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
Explain why, concave mirrors are used as shaving mirrors.
The angle of incidence for of light passing through the centre of curvature of a concave mirror is:
(a) 45°
(b) 90°
(c) 0°
(d) 180°
When an object is placed at a distance of 15 cm from a concave mirror, its image is formed at 10 cm in front of the mirror. Calculate the focal length of the mirror.
The mirror which can form a magnified image of an object is:
(a) convex mirror
(b) plane mirror
(c) concave mirror
(d) both convex and concave mirror
Name the lens which can concentrate sun's rays to a point and burn a hole in a piece of paper.
In the following diagram. MM' is a concave mirror and AB is an object. Draw on your answer-sheet a ray diagram to show the formation of image of this object.
A student has focused the image of a candle flame on a white screen using a concave mirror. The situation is as given below:
Length of the flame = 1.5 cm
Distance of flame from the mirror = 18 cm
If the flame is perpendicular to the principal axis of the mirror, then calculate the following:
- Distance of the image from the mirror
- Length of the image
If the distance between the mirror and the flame is reduced to 10 cm, then what would be observed on the screen? Draw ray diagram to justify your answer for this situation.
Write the uses of the concave mirror.
