1
WB JEE 2023
MCQ (Single Correct Answer)
+2
-0.5
Change Language

There are n elastic balls placed on a smooth horizontal plane. The masses of the balls are $$\mathrm{m}, \frac{\mathrm{m}}{2}, \frac{\mathrm{m}}{2^{2}}, \ldots \frac{\mathrm{m}}{2^{\mathrm{n}-1}}$$ respectively. If the first ball hits the second ball with velocity $$\mathrm{v}_{0}$$, then the velocity of the $$\mathrm{n}^{\text {th }}$$ ball will be,

A
$$\frac{4}{3} v_{0}$$
B
$$\left(\frac{4}{3}\right)^{n} v_{0}$$
C
$$\left(\frac{4}{3}\right)^{n-1} v_{0}$$
D
$$\mathrm{v}_{0}$$
2
WB JEE 2023
MCQ (Single Correct Answer)
+2
-0.5
Change Language

An earth's satellite near the surface of the earth takes about 90 min per revolution. A satellite orbiting the moon also takes about $$90 \mathrm{~min}$$ per revolution. Then which of the following is true?

[where $$\rho_{\mathrm{m}}$$ is density of the moon and $$\rho_{\mathrm{e}}$$ is density of the earth.]

A
$$\rho_{\mathrm{m}}<\rho_{\mathrm{e}}$$
B
$$\rho_{m}>\rho_{e}$$
C
$$\rho_{m}=\rho_{e}$$
D
No conclusion can be made about the densities.
3
WB JEE 2023
MCQ (Single Correct Answer)
+2
-0.5
Change Language

WB JEE 2023 Physics - Magnetism Question 3 English

A bar magnet falls from rest under gravity through the centre of a horizontal ring of conducting wire as shown in figure. Which of the following graph best represents the speed (v) vs. time (t) graph of the bar magnet?

A
WB JEE 2023 Physics - Magnetism Question 3 English Option 1
B
WB JEE 2023 Physics - Magnetism Question 3 English Option 2
C
WB JEE 2023 Physics - Magnetism Question 3 English Option 3
D
WB JEE 2023 Physics - Magnetism Question 3 English Option 4
4
WB JEE 2023
MCQ (More than One Correct Answer)
+2
-0
Change Language

A uniform magnetic field B exists in a region. An electron of charge q and mass m moving with velocity v enters the region in a direction perpendicular to the magnetic field. Considering Bohr angular momentum quantization, which of the following statements is/are true?

A
The radius of nth orbit $$\mathrm{r_n~\infty ~\sqrt n}$$.
B
The minimum velocity of the electron is $$\frac{\sqrt{\mathrm{qB} \hbar}}{\mathrm{m}}$$.
C
Energy of the $$\mathrm{n}^{\text {th }}$$ level $$E_{n} ~\infty~n$$.
D
Transition frequency $$\omega$$ between two successive levels is independent of n.
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