Following figure illustrates the ray diagram for  the formation of images by a concave mirror. The  position of the object is beyond the centre of  curvature of the concave mirror. On the basis of the given diagram, answer any four questions from (a)  to (e).  

Question 1.jpg






(a) If the focal length of the concave mirror is 10 cm,  the image formed will be at a distance  ___________.  

(i) Between 10cm and 15cm  

(ii) Between 10cm and 20cm  

(iii) Beyond 20cm  

(iv) At 20 cm  

 

Ans. 

  • As seen from the figure, the image formed is between focus and centre of curvature
  • Thus, Image is formed between 10 and 20 cm.

So, the correct answer is (ii)



(b) In case of a concave mirror, the image distance is  _________ when image is formed in front of the  mirror and _________________ when the image  is formed behind the mirror.  

(i) positive, negative  

(ii) negative, negative 

(iii) negative, positive  

(iv) positive, positive  

 

Ans. 

sign-convention-for-mirrors---teachoo.jpg

According to the sign convention for concave mirror 

  •  The image distance is negative when the image is formed in front of the mirror
  •  The image distance is positive when the image   is formed behind the mirror

 

So, the correct answer is (iii) - negative, positive  

 

(c) If the size of the object in the given figure is 5 cm  and the magnification produced is –0.5. The size  of the image is (in cm) ___________  

(i) –2.5 

(ii) –0.1  

(iii) 2.5 

(iv) 0.1  

 

Ans.  

Slide1.JPG

Slide2.JPG

 

So, the correct answer is  (i) – 2.5 

 

(d) A negative sign in the magnification value  indicate that the image is  ____________   

(i) Real and inverted  

(ii) Real and erect  

(iii) Virtual and erect  

(iv) Virtual and inverted  

 

Ans.

sign-convention-for-mirrors---teachoo.jpg

Slide1.JPG

So, the correct answer is (i) Real and inverted

 

(e) An image formed by concave mirror is virtual,  when the object is placed:  

(i) at infinity 

(ii) at C  

(iii) Between C and F 

(iv) Between P and F  

 

Ans. 

concave-mirror-object-between-pole-(p)-&-focus-(f)--teachoo.jpg

From figure we note that:

  • If we place Object between P ole and F ocus
  • Concave mirror forms virtual and erect images.

 

So, the correct answer is (iv) = Between P and F

  1. Class 10
  2. Chapter 10 Class 10 - Light - Reflection and Refraction (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo