Reflection of light Notes for Class 10

Image formation by concave mirror

  • The type of image formed by a concave mirror depends on the position of the object kept in front of the mirror. We can place the object at following places
    1. Between pole P and focus F
    2. At the focus
    3. Between focus F and centre of curvature C
    4. At the centre of curvature
    5. Beyond center of curvature
    6. At far off distances called infinity and cannot be shown in the figures
  • Image formation by a concave mirror for different positions of the object is shown below in the table Image formation by concave mirror
  • Concave mirrors are used as shaving mirrors, reflectors in car headlights, hand torch and table lamps.
  • Large concave mirrors are used in field of solar energy to focus sun rays on objects to be heated.

Image formation by convex mirrors

  • In order to construct a ray diagram to find out the position, nature and size of image formed by convex mirror we should remember following path of rays of light.
  • A ray of light parallel to the principle axis of a convex mirror appears to be coming from its focus after reflection from the mirror.
  • A ray of light going towards the centre of curvature of convex mirror is reflected back along its own path.
  • Convex mirrors have its focus and center of curvature behind it and no light can go behind the convex mirror and all the rays that we show behind the convex mirror are virtual and no ray actually passes through the focus and center of curvature of the convex mirror.
  • Whatever be the position of object in front of convex mirror, the image formed by a convex mirror is always behind the mirror, virtual, erect and smaller than the object.
  • Nature, position and relative size of the image formed by a convex mirror is given below in the table Image formation by convex mirrors
  • Convex mirrors are used as rear view mirrors in automobiles to see the traffic at back side as they give erect images and also highly diminished one giving the wide field view of traffic behind.

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Class 10 Maths Class 10 Science

Practice Question

Question 1 Which among the following is not a base?
B) $NH_4OH$
C) $C_2H_5OH$
Question 2 What is the minimum resistance which can be made using five resistors each of 1/2 Ohm?
A) 1/10 Ohm
B) 1/25 ohm
C) 10 ohm
D) 2 ohm
Question 3 Which of the following statement is incorrect? ?
A) For every hormone there is a gene
B) For production of every enzyme there is a gene
C) For every molecule of fat there is a gene
D) For every protein there is a gene