Check sibling questions

A student wants to project the image of a candle  flame on a screen 60 cm in front of a mirror by  keeping the flame at a distance of 15 cm from its  pole.  


(a) Suggest the type of mirror he should use:  

(i) convex mirror 

(ii) plane mirror  

(iii) concave mirror 

(iv) none of the above  




Since the student wants image on a screen , it has to be a real image


Now, let’s check both mirrors

  • Convex mirrors always produce virtual images . It cannot be used to produce images on the screen.
  • Concave mirrors produce real images on the screen in all cases except when the object is between pole and focus , therefore students should use a concave mirror because it forms real images.
  • Plane mirrors always form virtual images. So, it cannot be used


So, the correct answer is (iii) Concave mirror  

(b) Find the linear magnification of the image  produced.  

(i) – 4 

(ii) + 4  

(iii) – 900 

(iv) + 900  



So, the correct answer is (i) – 4 

(c) When object distance is less than focal length the image is _______ and when object distance is more  than focal length the image is  ______.  

(i) real, real 

(ii) virtual. Virtual  

(iii) real, virtual 

(iv) virtual, real



In a concave mirror

  • When object is kept between Focus and Pole , image formed is virtual
  • When object is kept beyond focus (between C and F, at C and beyond C), image formed is real 


So, the correct answer is (iv) virtual, real 


(d) Draw  a ray diagram for the given scenario. 





(e) What is the distance between the object and its image?  

(i) 15 cm 

(ii) 45 cm  

(iii) 75 cm 

(iv) 0 cm  





Object distance, u = -15cm

Image distance, v = -60cm



Distance between object and image = u - v 

= -15 - (-60)

= 45cm


The correct answer is (ii) 15 cm 

(e) The image formed in the above case is:  

(i) virtual, inverted and magnified.  

(ii) real, erect and magnified  

(iii) real, inverted and magnified  

(iv) real, erect and diminished  



  • Since the image is formed on a screen , it is real .


Also, we calculated the magnification of the image as m= -4. 

  • Since M = image size/object size, it is clear that the image is 4 times larger than the object. 
  • Hence it is magnified. 
  • The negative sign in the magnification means that the image is inverted.  

Thus, the correct answer is (i) real, inverted and magnified

983 students joined Teachoo Black. What are you waiting for?

CA Maninder Singh's photo - Expert in Practical Accounts, Taxation and Efiling

Made by

CA Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 12 years and a teacher from the past 16 years. He teaches Science, Accounts and English at Teachoo