Spherical Mirror 10th class (lec-3)

 video lecture for Spherical Mirror

Question 1: The laws of reflection hold true for

(a) plane mirrors only
(b) concave mirrors only
(c) convex mirrors only
(d) all reflecting surface

Question 2. List four characteristics of the images formed by plane mirrors. (Delhi 2015, AI2011)

Question 3. State the two laws of reflection of light. (Delhi 2011)

Question 4. When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. This image is

(a) real

(b) inverted

(c) virtual and inverted

(d) virtual and erect (2020)

Question 5. Draw a labelled ray diagram to show the path of the reflected ray corresponding to an incident ray of light parallel to the principal axis of a convex mirror. Mark the angle of incidence and angle of reflection on it. (AI 2019)

Question 6. If the image formed by a spherical mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a labelled ray diagram to support your answer. (2018)

Question 7. A ray of light is incident on a convex mirror as shown. Redraw the diagram and complete the path of this ray after reflection from the mirror. Mark angle of incidence and angle of reflection on it. (Delhi 2016)

Question 8. Name the type of mirrors used in the design of solar furnaces. Explain how high temperature is achieved by this device. (AI 2016)

Question 9. List two properties of the images formed by convex mirrors. Draw a ray diagram in support of your answer. (Foreign 2016)

Question 10. Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray which is directed towards the principal focus of a convex mirror. Mark on it the angle of incidence and the angle of reflection. (Delhi 2014)

Question 11. Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray which is directed parallel to the principal axis of a convex mirror, Mark on it the angle of incidence and the angle of reflection. (Delhi 2014)

Question 12. Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray of light parallel to the principal axis of a concave mirror. Mark the angle of incidence and angle of reflection on it. (Delhi 2014)

Question 13. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should the position of the object be relative to the mirror? Draw ray diagram to justify your answer. (AI 2014)

Question 14. Draw ray diagrams for the following cases when a ray of light:

(i) passing through centre of curvature of a concave mirror is incident on it.

(ii) parallel to principal axis is incident on convex mirror.

(iii) is passing through focus of a concave mirror incident on it. (2020)

Question 15. Draw the following diagram in which a ray of light is incident on a concave/convex mirror, on your answer sheet. Show the path of this ray, after reflection, in each case.

Answer:

Question 16. Mention the types of mirrors used as (i) rear view mirrors, (ii) shaving mirrors. List two reasons to justify your answer in each case. (Delhi 2013, Delhi 2012)

Question 17. State the types of mirrors used for (i) headlights and (ii) rear view mirrors, in motorcycles. Give reason to justify your answer in each case. (AI 2012)

Question 18. An object is placed between infinity and the pole of a convex mirror. Draw a ray diagram and also state the position, the relative size and the nature of the image formed. (AI 2011)

Question 19. With the help of a ray diagram explain why a convex mirror is preferred for rear view mirrors in the motor cars. (Foreign 2011)

Question 20. (a) Define the following terms in the context of spherical mirrors:

(i) Pole

(ii) Centre of curvature

(iii) Principal axis

(iv) Principal focus

(b) Draw ray diagrams to show the principal focus of a

(i) Concave mirror (ii) Convex mirror

(c) Consider the following diagram in which M is a mirror and P is an object and Q is its magnified image formed by the mirror.

State the type of the mirror M and one characteristic property of the image Q. (Delhi 2016)

Answer Key

Q1: Answer:
(d) The laws of reflection holds true for all reflecting surface.

Q2: Answer: Characteristics of the image formed by a plane mirror are

(i) imagedistanceissameasthatofobjectdistance
(ii) image formed is virtual and erect
(iii) image formed is of the same size as that of the object
(iv) image formed is laterally inverted (left appears right and right appears left).

Q3: Answer: Laws of reflection of light states that

(i) The angle of incidence is equal to the angle of reflection.
(ii) The incident ray, the reflected ray and the normal to the mirror at the point of incidence all lie in the same plane.

Q4: Answer:

(d) When an object is placed between the principal focus and pole of a concave mirror, an enlarged virtual and erect image is formed behind the mirror.

Q5: Answer: 

Q6: Answer:

If the image formed by a spherical mirror is always erect and diminished then it is a convex mirror.

Q7: Answer:

Q8: Answer:

Concave mirrors are used in the designing of solar furnaces.

When a solar furnace is placed at the focus of a large concave mirror, it focuses a parallel beam of light on the furnace. Therefore, a high temperature is attained at the point after some time.

Q9: Answer:

Convex mirrors always form diminished, virtual and erect images.

Q10: Answer:

Q11: Answer:

Q12: Answer:

Q13: Answer:

The position of the object should be between `P` and `F`

Q14: Answer:

(i) Ray of light passing through centre of curvature of concave mirror, after reflection

(ii) Ray of light parallel to the principal axis is incident on a convex mirror after reflection appear to diverge from the principal focus of a convex mirror.

(iii) Ray of light passing through focus of a concave mirror after reflection will emerge parallel

Q15: Answer: The path of the rays are shown in figure.

Q16: Answer:

(i) Convex mirror is used as rear view mirror because

(a) it gives erect image.

(b) it gives diminished image thus provides wider view of traffic behind the vehicle.

(ii) Concave mirror is used as shaving mirror because

(a) it gives erect image when mirror is close to the face.

(b) it gives enlarged image of the face so that a person can shave safely.

Q17: Answer:

(i) Concave mirrors are used in headlights of cars to get powerful beams of light.

(ii) Convex mirrors are used as rear-view mirrors of vehicle to get a wider field of view and and erect image of traffic behind.

Q18: Answer:

Position: Image is formed between pole and principal focus of the mirror.

Relative size : Image formed is diminished.

Nature : Image formed is virtual and erect.

Q19: Answer:

Convex mirror is preferred for rear view mirrors in motor cars because no matter where the object is located in front of convex mirror, it always gives erect and diminished image of the object, so that driver is able to see the large traffic view in small area and the image is erect. This can be interpreted from the following diagram.

Q20: Answer:

(a) (i) Pole : The centre of the reflecting surface of a spherical mirror is a point called the pole. It lies in the surface of the mirror and its represented by the letter P.

(ii) Centre of curvature: The reflecting surface of a spherical mirror is a part of a sphere which has a centre. This point is called the centre of curvature of spherical mirror and is represented by the letter C.

(iii) Principal axis : An imaginary line passing through the pole and the centre of curvature of a spherical mirror and normal to the mirror at its pole is called principal axis.

(iv) Principal focus : Incident rays parallel to principal axis, after reflection either converge to as appear to diverge from a fixed point on the principal axis known as principal focus of the spherical mirror.

(c) The object is placed between focus and pole of the mirror and a magnified image is formed behind the mirror.

∴ The mirror is concave and image formed is virtual and erect.