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Page No 171: - Chapter 10 - Light - Reflection & Refraction - Ncert Solutions class 10 - Science


Question 1:

Find the focal length of a convex mirror whose radius of curvature is 32 cm.

Answer:

Radius of curvature, R = 32 cm

Radius of curvature = 2 × Focal length (f)

R = 2f

https://img-nm.mnimgs.com/img/study_content/curr/1/10/10/154/983/Chapter%2010_html_7ecf03b6.gif

Hence, the focal length of the given convex mirror is 16 cm.

Question 2:

A concave mirror produces three times magnified (enlarged) real image of object placed at 10 cm in front of it. Where is the image located?

Answer:

Magnification produced by a spherical mirror is given by the relation,

https://img-nm.mnimgs.com/img/study_content/curr/1/10/10/154/986/Chapter%2010_html_27af01eb.gif

Let the height of the object, ho = h

Then, height of the image, hI = −3h (Image formed is real)

https://img-nm.mnimgs.com/img/study_content/curr/1/10/10/154/986/Chapter%2010_html_1f6675f2.gif

Object distance, u = −10 cm

v = 3 × (−10) = −30 cm

Here, the negative sign indicates that an inverted image is formed at a distance of 30 cm in front of the given concave mirror.