/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 183 A thin convex lens made from cro... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

A thin convex lens made from crown glass \(\left(\mu=\frac{3}{2}\right)\) has focal length \(f\). When it is measured in two different liquids having refractive indices \(\frac{4}{3}\) and \(\frac{5}{3}\), it has the focal lengths \(f_{1}\) and \(f_{2}\), respectively. The correct relation between the focal lengths is (A) \(f_{1}=f_{2}f\) and \(f_{2}\) becomes negative (C) \(f_{2}>f\) and \(f_{1}\) becomes negative (D) \(f_{1}\) and \(f_{2}\) both become negative

Short Answer

Expert verified
Based on the computation, the correct answer is (D) - \(f_{1}\) and \(f_{2}\) both become negative when the lens is immersed in both liquids.

Step by step solution

01

Lens in Air

Initially, the lens is in air, and the refractive index of air is 1. So, applying the lens-maker's formula, the focal length of the lens is given as \(\tfrac{1}{f} = \tfrac{\mu - 1}{1} \times (\tfrac{1}{R_1}-\tfrac{1}{R_2})\).
02

Lens in First Liquid

When the lens is placed in the first liquid with a refractive index of \(\tfrac{4}{3}\), the formula changes to \(\tfrac{1}{f_{1}} = \tfrac{\tfrac{3}{2} - \tfrac{4}{3}}{\tfrac{4}{3}} \times (\tfrac{1}{R_1} - \tfrac{1}{R_2})\). This simplifies to \(\tfrac{1}{f_{1}} = \tfrac{-2}{3} \times (\tfrac{1}{R_1} - \tfrac{1}{R_2})\). Seeing that the right-hand side is negative, which implies \(f_{1}<0\). Therefore, the focal length becomes negative in the first liquid.
03

Lens in Second Liquid

When the lens is placed in the second liquid with refractive index of \(\tfrac{5}{3}\), the formula changes to \(\tfrac{1}{f_{2}} = \tfrac{\tfrac{3}{2} - \tfrac{5}{3}}{\tfrac{5}{3}} \times (\tfrac{1}{R_1} - \tfrac{1}{R_2})\). This simplifies to \(\tfrac{1}{f_{2}} = \tfrac{-1}{5} \times (\tfrac{1}{R_1} - \tfrac{1}{R_2})\), which also implies that \(f_{2}<0\). Therefore, the focal length becomes negative in the second liquid.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The light ray is incident at angle of \(60^{\circ}\) on a prism of angle \(45^{\circ}\). When the light ray falls on the other surface at \(90^{\circ}\), the refractive index of the material of prism \(\mu\) and the angle of deviation \(\delta\) are given by (A) \(\mu=\sqrt{\frac{3}{2}}, \delta=30^{\circ}\) (B) \(\mu=1.5, \delta=15^{\circ}\) (C) \(\mu=\frac{\sqrt{3}}{2}, \delta=30^{\circ}\) (D) \(\mu=\sqrt{\frac{3}{2}}, \delta=15^{\circ}\)

Match the statement given in Column-I with those given in Column-II. \begin{tabular}{ll} \hline \multicolumn{1}{c} { Column-I } & \multicolumn{1}{c} { Column-II } \\ \hline (A) & In refraction & 1\. Speed of wave \\ & does not change \\ (B) & In reflection & 2\. Wavelength is decreased \\ \(\begin{array}{ll}\text { (C) } & \text { In refraction of a ray } \\ \text { moving from rarer to a } \\ \text { denser medium. }\end{array}\) & 3\. Frequency doesn't change \\ (D) & In reflection of a ray & 4\. Phase change of \\ & moving in rarer from a denser medium. & place \end{tabular}

A fish looks up through the water sees the outside world contained in a circular horizon. If the refractive index of water is \(4 / 3\) and the fish is \(12 \mathrm{~cm}\) below the surface, the radius of this circle in \(\mathrm{cm}\) is \(\quad\) [2005] (A) \(\frac{36}{\sqrt{7}}\) (B) \(36 \sqrt{7}\) (C) \(4 \sqrt{5}\) (D) \(36 \sqrt{5}\)

In YDSE distance between the slits plane and screen is \(1 \mathrm{~m}\) and distance between two slits is \(5 \mathrm{~mm}\). If slabs of thickness \(2 \mathrm{~mm}\) and \(1.5 \mathrm{~mm}\) having refractive index \(1.5\) and \(1.4\) are placed in front of two slits, the shift of central maximum will be (A) \(2 \mathrm{~m}\) (B) \(8 \mathrm{~cm}\) (C) \(20 \mathrm{~cm}\) (D) \(80 \mathrm{~cm}\)

The refractive index of a glass is \(1.520\) for red light and \(1.525\) for blue light. Let \(D_{1}\) and \(D_{2}\) be angles of minimum deviation for red and blue light, respectively, in a prism of this glass. Then, [2006] (A) \(D_{1}D_{2}\)

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.