JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
The radius of curvature for a thin convex lens are 10 cm and 15 cm respectively. The focal length of the lens is 12 cm. The refractive index of the lens material is :
- A 1.2
- B 1.4
- C 1.5
- D 1.8
Answer & Solution
Correct Answer
(C) 1.5
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & \frac{1}{\mathrm{f}}=(\mu-1)\left(\frac{1}{\mathrm{R}_1}-\frac{1}{\mathrm{R}_2}\right) \\ & \frac{1}{12}=(\mu-1)\left(\frac{1}{10}-\frac{1}{-15}\right) \\ & \frac{1}{12}=(\mu-1)\left(\frac{3+2}{30}\right) \\ & \mu=\frac{3}{2}\end{aligned}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- A thin disc of radius \(b = 2a\) has a concentric hole of radius \('a'\) in it (see figure). It carries uniform surface charge \('\sigma '\) on it. If the electric field on its axis at height \('h'\) \((h << a)\) from its centre is given as \('Ch'\) then value of \('C'\) is
JEE Mains 2015 Hard - A water drop of diameter \(cm\) is broken into \(64\) equal droplets. The surface tension of water is \(0.075\,N / m\). In this process the gain in surface energy will be ...........\(J\)JEE Mains 2022 Hard
- A thin uniform tube is bent into a circle of radius \(r\) in the virtical plane. Equal volumes of two immiscible liquids, whose densities are \({\rho _1}\) and \({\rho _2}\left( {{\rho _1} > {\rho _2}} \right)\) fill half the circle. The angle \(\theta\) between the radius vector passing through the common interface and the vertical isJEE Mains 2018 Hard
- Match list-\(I\) with list-\(II\):
(Where \(\mathrm{a}=\) radius of planet orbit, \(\mathrm{r}=\) radius of planet, \(M=\) mass of Sun, \(m=\) mass of planet)List-\(I\) List-\(II\) \((A)\)Kinetic energy of plant \((I)\) \(-\frac{\mathrm{GMm}}{\mathrm{a}}\) \((B)\) Gravaitatioin potentiyal energy of sun -plant system \((II)\) \(\frac{\mathrm{GMm}}{2 \mathrm{a}}\) \((C)\)Total mecaniacal energy of palnt \((III)\) \(\frac{\mathrm{Gm}}{\mathrm{r}}\) \((D)\)Escap energyat the surface of plant for unit mass object \((IV)\) \(-\frac{\mathrm{GMm}}{2 \mathrm{a}}\)
Choose the correct answer from the options given below:JEE Mains 2024 Hard - A prism of angle \(A=1^{\circ}\) has a refractive index \(\mu=1.5 .\) A good estimate for the minimum angle of deviation (in degrees) is close to \(N/10\) Value of \(N\) is......JEE Mains 2020 Medium
- A monoatomic gas at pressure \(P\) and volume \(V\) is suddenly compressed to one eighth of its original volume. The final pressure at constant entropy will be \(.....P\)JEE Mains 2022 Hard
More PYQs from JEE Mains
- For three unit vectors \(\vec{a}, \vec{b}, \vec{c}\) satisfying \({|\vec{a}-\vec{b}|^{2}}+{|\vec{b}-\vec{c}|^{2}}+{|\vec{c}-\vec{a}|^{2}}=9\) and \({|2\vec{a}+k\vec{b}+k\vec{c}|}=3\), the positive value of k is:JEE Mains 2026 Medium
- The dimensional formula of angular impulse is _______.JEE Mains 2024 Hard
- To establish an instantaneous current of \(2\,A\) through a \(1\,\mu F\) capacitor ; the potential difference across the capacitor plates should be changed at the rate ofJEE Mains 2013 Medium
- If \(\mathrm{n}\) is the number of ways five different employees can sit into four indistinguishable offices where any office may have any number of persons including zero, then \(\mathrm{n}\) is equal to :JEE Mains 2024 Medium
- On the ellipse \(\frac{x^{2}}{8}+\frac{y^{2}}{4}=1\) let \(P\) be a point in the second quadrant such that the tangent at \(\mathrm{P}\) to the ellipse is perpendicular to the line \(x+2 y=0\). Let \(S\) and \(\mathrm{S}^{\prime}\) be the foci of the ellipse and \(\mathrm{e}\) be its eccentricity. If \(\mathrm{A}\) is the area of the triangle \(SPS'\) then, the value of \(\left(5-\mathrm{e}^{2}\right) . \mathrm{A}\) is :JEE Mains 2021 Hard
- Let \(A\) be the point of intersection of the lines \(L_1: \frac{x-7}{1}=\frac{y-5}{0}=\frac{z-3}{-1}\) and \(L_2: \frac{x-1}{3}=\frac{y+3}{4}=\frac{z+7}{5}\). Let \(B\) and \(C\) be the point on the lines \(L_1\) and \(L_2\) respectively such that \(\mathrm{AB}=\mathrm{AC}=\sqrt{15}\). Then the square of the area of the triangle ABC is :JEE Mains 2025 Medium