Question

Suppose you have three concave mirrors A, B and C of focal lengths 10cm, 15cm and 20cm. For each concave mirror you perform the experiment of image formation for three values of object distance of 10cm, 20cm and 30cm. Giving reason answer the following:
a) For the three object distance, identify the mirror/mirrors which will form an image of magnification
b) Out of the three mirrors identify the mirror which would be preferred to be used for shaving purposes/makeup

Answer 1

a) All the mirrors will give magnified images.
This is because in A the object is at the focus and in B and C the objects are between focus and centre of curvature.

b) All the mirrors can be used as shaving mirrors as they are all concave mirrors but if the question is about in which situation one can use the mirror as shaving mirror then non of it. Because the object should be placed between focus and pole to be used as a shaving or makeup mirror.

Hope to like the answer.

Answer 2

Hi Hope This Helps You  

Given, ,fa = 10 cm; fb = 15 cm; .fc = 20 cm u1 = 10 cm; u2 = 20 cm; u3 = 30 cm  

(a) m = -1 means u =2f . For A it will be u2 and for B it will be u3.

(b) Mirror B or C can be used for shaving/makeup purposes because the distance should be less than focal length for erect and magnified image. The face is generally kept at a distance more than 10 cm from the mirror.  

(c) When a = 10 cm Read more on Sarthaks.com - https://www.sarthaks.com/22887/suppose-you-have-three-concave-mirrors-a-b-and-c-of-focal-lengths-10-cm-15-cm-and-20-cm