NCERT Solutions for Class 10 Science Chapter 10
Important Board Questions
Light – Reflection and Refraction
NCERT Books for Session 2022-2023
CBSE Board and UP Board
3 Marker Questions
Questions No: 10
An object is placed at a distance of 15 cm from a concave lens of focal length 30 cm. List four characteristic (nature, position, etc.) of the image formed by the lens.
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The focal length of the lens(f), the image distance(v) and the object distance(u) are related as follows:
1/f = (1/v) – (1/u)
Here, focal length(f) = 15cm
Object distance(u) = – 30cm
Therefore, finding the image distance(u) using the above mentioned formula:
v= -10cm
From this we can get to know the important characteristics of the image:
1. Image is erect/upright.
2. Image is virtual.
3.Image is reduced in size.
4.Image is formed at a distance of 10 cm from the optical centre and on the same side in which the object is placed.