CUET · PHYSICS · PYQ PAPER 2023
A convex lens of glass (n = 1.5) has a focal length 18 cm in air. When it is immersed in water (n = 4/3) the focal length increases to:
- A 18 cm
- B 36 cm
- C 54 cm
- D 72 cm
Answer & Solution
Correct Answer
(D) 72 cm
Step-by-step Solution
Detailed explanation
\( \frac{f_m}{f_a} = \frac{(n_g - 1)}{\left( \frac{n_g}{n_m} - 1 \right)} \) \( f_m = 18 \frac{(1.5 - 1)}{\left( \frac{1.5}{4/3} - 1 \right)} = 18 \frac{0.5}{\left( \frac{4.5}{4} - 1 \right)} \) \( f_m = 18 \frac{0.5}{0.125} = 18 \times 4 \) \( f_m = 72 \text{ cm} \)
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 very long solenoid has 800 turns per unit length. A current of 1.6 A flows through it. Then the magnetic induction in the middle of the solenoid on its axis is approximately :
(1) \( 16 \times 10^{-4} \text{ T} \)
(2) \( 8 \times 10^{-4} \text{ T} \)
(3) \( 32 \times 10^{-4} \text{ T} \)
(4) \( 4 \times 10^{-4} \text{ T} \)CUET 2023 Hard - A closely wound solenoid of 1000 turns and area of cross section \( 1.2 \text{ cm}^2 \) carries a current of 5 A. It is suspended horizontally in uniform magnetic field of \( 5 \times 10^{-2} \text{ T} \) making an angle of \( 30^\circ \) with the axis of solenoid. The torque acting on the solenoid is:CUET 2023 Easy
- Arrange these in ascending order of wavelength while propagating through different medium.
(A) Light propagating in air
(B) Light propagating in water
(C) Light propagating in diamond
(D) Light propagating in glass
Choose the correct answer from the options given below :CUET 2023 Hard - Diodes are most commonly used for rectification of alternating voltages. This is because, in diode
(A) current flows in one direction only
(B) forward bias resistance is low as compared to reverse bias resistance
(C) reverse current is independent of the voltage applied
(D) reverse current is linearly dependent on the voltage applied
Choose the correct answer from the options given below:CUET 2025 Medium - A charged particle is released from rest in a region of a uniform magnetic field along the direction of the magnetic field. The path of the charged particle in the magnetic field will beCUET 2025 Easy
- Two identical circular loops P and Q each of radius R and carrying current I are kept in perpendicular planes such that they have a common centre as shown in figure. The magnitude of the net magnetic field at the common centre is :
CUET 2023 Medium
More PYQs from CUET
- The area of a triangle having the points \(A (1,1,1), B (1,2,3)\) and \(C (2,3,1)\) as its vertices is :CUET 2023 Medium
- For a heavily doped n-type semiconductor, Fermi level lies:CUET 2023 Medium
- An astronomical telescope has a large aperture toCUET 2025 Hard
- Which of the following shows the correct relation between electric Intensity \(E\), and electric potential \(V\) :CUET 2023 Easy
- In gamma ray emission from a nucleus.CUET 2023 Medium
- The elucidation of the lac operon was the result of close association between the geneticist ______ and the biochemist ______.CUET 2023 Easy