1
JEE Main 2026 (Online) 22nd January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

When a part of a straight capillary tube is placed vertically in a liquid, the liquid raises upto certain height $h$. If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by $1 \%$ each, then the height of the liquid in the tube will change by $\_\_\_\_$ $\%$.

A

+3

B

+1

C

-1

D

-3

2
JEE Main 2026 (Online) 22nd January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below are two statements :

Statement I : A satellite is moving around earth in the orbit very close to the earth surface. The time period of revolution of satellite depends upon the density of earth.

Statement II : The time period of revolution of the satellite is $T=2 \pi \sqrt{\frac{R_e}{g}}$ (for satellite very close to the earth surface), where $R_{\mathrm{e}}$ radius of earth and $g$ acceleration due to gravity. In the light of the above statements, choose the correct answer from the options given below :

A

Statement I is true but Statement II is false

B

Statement I is false but Statement II is true

C

Both Statement I and Statement II are true

D

Both Statement I and Statement II are false

3
JEE Main 2026 (Online) 22nd January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Consider two boxes containing ideal gases $A$ and $B$ such that their temperatures, pressures and number densities are same. The molecular size of $A$ is half of that of $B$ and mass of molecule $A$ is four times that of $B$. If the collision frequency in gas $B$ is $32 \times 10^{18} / \mathrm{s}$ then collision frequency in gas $A$ is $\_\_\_\_$ /s.

A

$8 \times 10^{18}$

B

$2 \times 10^{18}$

C

$32 \times 10^{18}$

D

$4 \times 10^{18}$

4
JEE Main 2026 (Online) 22nd January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

In parallax method for the determination of focal length of a concave mirror, the object should always be placed:

A

between the focus $(F)$ and the centre of curvature $(C)$ of the mirror ONLY

B

between the pole $(P)$ and the focus $(F)$ of the concave mirror ONLY

C

at any point beyond the focus $(F)$ of the mirror

D

beyond the centre of the curvature $(C)$ of the mirror ONLY

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