SATHEE: Ray Optics and Optical Instruments

Ray Optics and Optical Instruments - Result Question 33

33. A biconvex lens has a radius of curvature of magnitude $20 c m$ . Which one of the following options best describe the image formed of an object of height $2 c m$ placed $30 c m$ from the lens?

(a) Virtual, upright, height $= 1 c m$

(b) Virtual, upright, height $= 0.5 c m$

[2011]

(d) Real, inverted, height $= 1 c m$

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Answer:

Correct Answer: 33. (c)

Solution:

$h_{0} = 2$

$u = - 30 c m$

We have, $\frac{1}{f} = (μ - 1) (\frac{1}{R_{1}} - \frac{1}{R_{2}})$

$= (\frac{3}{2} - 1) [\frac{1}{20} - (- \frac{1}{20})]$

$\Rightarrow \frac{1}{f} = (\frac{3}{2} - 1) \times \frac{2}{20}$

$∴ f = 20 c m$

$\frac{1}{f} = \frac{1}{v} - \frac{1}{u} \Rightarrow \frac{1}{20} = \frac{1}{v} + \frac{1}{30}$

$\frac{1}{v} = \frac{1}{20} - \frac{1}{30} = \frac{10}{600}$

$v = 60 c m$

$m = \frac{h_{i}}{h_{0}} = \frac{v}{u}$

$\Rightarrow h_{i} = \frac{v}{u} \times h_{0} = \frac{60}{30} \times 2 = - 4 c m$

So, image is inverted.

Ray Optics and Optical Instruments - Result Question 33

33. A biconvex lens has a radius of curvature of magnitude $20 c m$ . Which one of the following options best describe the image formed of an object of height $2 c m$ placed $30 c m$ from the lens?

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

Ray Optics and Optical Instruments - Result Question 33

33. A biconvex lens has a radius of curvature of magnitude 20cm. Which one of the following options best describe the image formed of an object of height 2cm placed 30cm from the lens?

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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33. A biconvex lens has a radius of curvature of magnitude $20 c m$ . Which one of the following options best describe the image formed of an object of height $2 c m$ placed $30 c m$ from the lens?