1
JEE Main 2025 (Online) 22nd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

In the diagram given below, there are three lenses formed. Considering negligible thickness of each of them as compared to $\left|R_1\right|$ and $\left|R_2\right|$, i.e., the radii of curvature for upper and lower surfaces of the glass lens, the power of the combination is

JEE Main 2025 (Online) 22nd January Morning Shift Physics - Geometrical Optics Question 34 English

A
$-\frac{1}{6}\left(\frac{1}{\left|\mathrm{R}_1\right|}-\frac{1}{\left|\mathrm{R}_2\right|}\right)$
B
$-\frac{1}{6}\left(\frac{1}{\left|\mathrm{R}_1\right|}+\frac{1}{\left|\mathrm{R}_2\right|}\right)$
C
$\frac{1}{6}\left(\frac{1}{\left|\mathrm{R}_1\right|}+\frac{1}{\left|\mathrm{R}_2\right|}\right)$
D
$\frac{1}{6}\left(\frac{1}{\left|\mathrm{R}_1\right|}-\frac{1}{\left|\mathrm{R}_2\right|}\right)$
2
JEE Main 2025 (Online) 22nd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A line charge of length $\frac{\mathrm{a}}{2}$ is kept at the center of an edge $B C$ of a cube ABCDEFGH having edge length ' $a$ ' as shown in the figure. If the density of line charge is $\lambda \mathrm{C}$ per unit length, then the total electric flux through all the faces of the cube will be ___________ . (Take, $\epsilon_0$ as the free space permittivity)

JEE Main 2025 (Online) 22nd January Morning Shift Physics - Electrostatics Question 33 English

A
$\frac{\lambda a}{2 \epsilon_0}$
B
$\frac{\lambda \mathrm{a}}{8 \epsilon_0}$
C
$\frac{\lambda \mathrm{a}}{4 \epsilon_0}$
D
$\frac{\lambda \mathrm{a}}{16 \epsilon_0}$
3
JEE Main 2025 (Online) 22nd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A bob of mass $m$ is suspended at a point $O$ by a light string of length $l$ and left to perform vertical motion (circular) as shown in figure. Initially, by applying horizontal velocity $v_0$ at the point ' A ', the string becomes slack when, the bob reaches at the point ' $D$ '. The ratio of the kinetic energy of the bob at the points B and C is _________.

JEE Main 2025 (Online) 22nd January Morning Shift Physics - Circular Motion Question 8 English

A
4
B
1
C
2
D
3
4
JEE Main 2025 (Online) 22nd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of

A
 Both Cs and Li
B
Neither Cs nor Li
C
Li only
D
Cs only
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