1
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

A radioactive nucleus decays as follows :

$$ X \xrightarrow{\alpha} X_1 \xrightarrow{\beta} X_2 \xrightarrow{\alpha} X_3 \xrightarrow{\gamma} X_4 $$

If the mass number and atomic number of ' $X_4$ ' are 172 and 69 respectively, then the atomic number and mass number of ' $X$ ' are

A
72,180
B
69,170
C
68,172
D
70,172
2
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

A single slit diffraction pattern is obtained using a beam of red light. If red light is replaced by blue light then

A
the diffraction pattern will disappear.
B
fringes will become narrower and crowded together.
C
fringes will become broader and will be further apart.
D
there is no change in the diffraction pattern.
3
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

The variation of density of a solid cylindrical rod of cross sectional area $\alpha$ and length $L$ is $\rho=\rho_0 \frac{x^2}{L^2}$, where $x$ is the distance from one end of the rod. The position of its centre of mass from one end $(x=0)$ is

WB JEE 2025 Physics - Center of Mass Question 2 English

A
$\frac{2 L}{3}$
B
$\frac{L}{2}$
C
$\frac{L}{3}$
D
$\frac{3 L}{4}$
4
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

A simple pendulum is taken at a place where its distance from the earth's surface is equal to the radius of the earth. Calculate the time period of small oscillations if the length of the string is 4.0 m . (Take $g=\pi^2 \mathrm{~ms}^{-2}$ at the surface of the earth.)

A
4 s
B
6 s
C
8 s
D
2 s
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12