Get Answers to all your Questions

header-bg qa

The power of a lens (biconvex) is 1.25 \mathrm{~m}^{-1} in particular medium. Refractive index of the lens is 1.5 and radii of curvature are 20 \mathrm{~cm}$ and $40 \mathrm{~cm} respectively. The refractive index of surrounding medium:
 

Option: 1

1.0


Option: 2

\frac{9}{7}


Option: 3

\frac{3}{2}


Option: 4

\frac{4}{3}


Answers (1)

best_answer

\mathrm{P=1.25m^{-1}}

\mathrm{\mu =1.5}

\mathrm{R_{1}=20cm,R_{2}=40cm}

\mathrm{P=\frac{1}{f} =\left(\mu_g^n-1\right)\left(\frac{1}{R_1}-\frac{1}{R_2}\right) }

\mathrm{\mu_g^m =\frac{\mu_g}{\mu_m}=\frac{1.5}{\mu_m} }

\mathrm{P =\left(\frac{1.5}{\mu_m}-1\right)\left(\frac{1}{+20}-\frac{1}{(-40)}\right) }

\mathrm{\frac{5}{4} =\left(\frac{1.5}{\mu_m}-1\right)\left(\frac{3}{40 \times 10^{-2}}\right) }

\mathrm{\frac{1}{6} =\frac{1.5}{\mu_m}-1 }

\mathrm{\frac{7}{6} =\frac{1.5}{\mu_m} }

\mathrm{\mu_m =\frac{9}{7}}

Hence 2 is correct option.







 

Posted by

mansi

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE