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प्रश्न
With the help of an appropriate ray diagram, state the sign conventions for reflection by a spherical mirror.
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उत्तर
The sign convention for reflection by spherical mirrors is as follows:-
- The object is always placed to the left of the mirror.
- All distances parallel to the principal axis are measured from the pole of the mirror.
- All the distances measured to the right of the origin are taken as positive, while those measured to the left of the origin are taken as negative.
- Distances measured perpendicular to and above the principal axis are taken as positive.
- Distances measured perpendicular to and below the principal axis are taken as negative.
- The focal length of a convex mirror is positive, while that of a concave mirror is negative.
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संबंधित प्रश्न
State two positions in which a concave mirror produces a magnified image of a given object. List two differences between the two images.
Draw ray diagrams to show the principal focus of a convex mirror.
A student has obtained the image of a distant object with a concave mirror to determine its focal length. If he has selected a well-illuminated red building as object, which of the following correctly describes the features of the image formed?
(A) Virtual, inverted and diminished image in red shade
(B) Real, erect and diminished image in pink shade
(C) Real, inverted and diminished image in red shade
(D) Virtual, erect and enlarged image in red shade
Name the type of mirror used in the following situation:
Headlights of a car
Support your answer with reason.
An object 4 cm in height, is placed at 15 cm in front of a concave mirror of focal length 10 cm. At what distance from the mirror should a screen be placed to obtain a sharp image of the object. Calculate the height of the image.
A ray of light is incident on a plane mirror making an angle of 90° with the mirror surface. The angle of reflection for this ray of light will be:
(a) 45°
(b) 90°
(c) 0°
(d) 60°
A concave mirror ______ rays of light whereas a convex mirror ______ rays of light.
What is the position of the image when an object is placed at a distance of 20 cm from a concave mirror of focal length 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?
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.
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.
To construct ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centre of curvature and focus of a concave mirror.
Why does obtaining the image of the sun on paper with the help of a concave mirror burn the paper?
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.
______ is used as reflectors in torchlight.
Concave mirrors are used by dentists to examine teeth. Why?
A child is standing in front of a magic mirror. She finds the image of her head bigger, the middle portion of her body of the same size and that of the legs smaller. The following is the order of combinations for the magic mirror from the top.
The concave reflecting surface of a torch got rusted. What effect would this have on the beam of light from the torch?
