1
WB JEE 2023
+1
-0.25 A wire carrying a steady current I is kept in the x-y plane along the curve $$y=A \sin \left(\frac{2 \pi}{\lambda} x\right)$$. A magnetic field B exists in the z-direction. The magnitude of the magnetic force in the portion of the wire between x = 0 and x = $$\lambda$$ is

A
0
B
2I$$\lambda$$B
C
I$$\lambda$$B
D
I$$\lambda$$B/2
2
WB JEE 2023
+2
-0.5  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 B C D 3
WB JEE 2022
+1
-0.25  Two infinite line-charges parallel to each other are moving with a constant velocity v in the same direction as shown in the figure. The separation between two line-charges is d. The magnetic attraction balances the electric repulsion when, [ c = speed of light in free space ]

A
$$v = \sqrt 2 c$$
B
$$v = {c \over {\sqrt 2 }}$$
C
$$v = c$$
D
$$v = {c \over 2}$$
4
WB JEE 2022
+1
-0.25 An electron revolves around the nucleus in a circular path with angular momentum $$\overrightarrow L$$. A uniform magnetic field $$\overrightarrow B$$ is applied perpendicular to the plane of its orbit. If the electron experiences a torque $$\overrightarrow T$$, then

A
$$\overrightarrow T ||\overrightarrow L$$
B
$$\overrightarrow T$$ is anti-parallel to $$\overrightarrow L$$
C
$$\overrightarrow T \,.\,\overrightarrow L = 0$$
D
Angle between $$\overrightarrow T$$ and $$\overrightarrow L$$ is $$45^\circ$$
WB JEE Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
Algebra
Trigonometry
Coordinate Geometry
Calculus
EXAM MAP
Medical
NEET