If the angle of incidence in a plane mirror is 15 degrees, what will be the angle of reflection? QUESTIONS 3.The normal to a mirror line can be described as:

A ray of light hits a plane mirror and bounces off of the mirror. the left side of the object becomes the right side of the image and vice-versa. The image formed in a plane mirror is laterally inverted i.e. Image distance is always equal to the object distance in a plane mirror. The image formed by a plane mirror is at the same distance behind the mirror as the object is in front of the mirror i.e. The image in a plane mirror is of the same size as the object. The image formed in a plane mirror is always erect. Such an image cannot be taken on a screen. The image formed in a plane mirror is always virtual. Thus disatnce between object and its image = 2(u-v).(2)įrom equations (1) and (2) distance between image and object isreducedby 2v units in unit time(1 second) Thus distance between mirror and object in unit time = u - v

Now if mirroe is approaching you/object with speed v, then distance travelled by mirror in unit time = v units Thus distance between image and object = 2u. Then distance of image = -u (as the image is formed at othersideof the mirror) Solution: Detailed explanation is here: Distance of Image formed in the mirror is same as the distance of the object form thesurfaceof the mirror. A plane mirror is a highly polished plane surface.ĬHARACTERISTICS OF IMAGE FORMED BY PLANE MIRRORS:įollowing are the important characteristics of image formed by plane mirrors.Įx. If the object moves with a velocity 'u' then the image moves with velocity 2u.how? (f) State one change the student should make to the apparatus if he wants to use the same method to investigate diffuse reflection.Any smooth, highly polished reflecting surface is called a mirror.

Results could be collected for angles of incidence not yet measured such as 10º and 60º (e) What extra evidence could be collected to support the student's conclusion? You could work out the average for each angle and the range of measurements to illustrate your answer. However uncertainties increase as the angle of incidence gets larger. For most of the angles eg at 20º / 30º / 40º there is at least one measurement of angle of reflection that is exactly the same and the others are close. Within the limits of experimental error the angle of incidence and the angle of reflection are equal. Use examples from the results in the table in your answer. Explain whether you agree with this conclusion. (d) The student concluded that for a plane mirror, the angle of incidence is equal to the angle of reflection. Show how you determine your estimate.Īt 50° the largest reading was 56° and the smallest was 46° so the range = 56° - 46° = 10° (c) Estimate the uncertainty in the angle of reflection when the angle of incidence is 50°. Just saying 'moving the mirror / ray box' was considered insufficient to get you the mark - as was 'measuring the angle incorrectly'. Not replacing mirror and or ray box in the same position each time. (b) Suggest what the student may have done during the investigation to cause each angle of reflection to have a range of values. What type of error will have caused each angle of reflection to have a range of values? (a) For each angle of incidence, the angle of reflection has a range of values.

A Level and AS level - UK KS 5 (Age 16 - 18).

GCSE and 'O' Level - UK KS4 (Age 14 - 16).

Angle of reflection on a plane mirror