1
WB JEE 2022
MCQ (Single Correct Answer)
+2
-0.5
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A horizontal semi-circular wire of radius r is connected to a battery through two similar springs X and Y to an electric cell, which sends current I through it. A vertically downward uniform magnetic field B is applied on the wire, as shown in the figure. What is the force acting on each spring?

WB JEE 2022 Physics - Magnetism Question 8 English

A
$$2\pi rBI$$
B
$${1 \over 2}\pi rBI$$
C
$$BIr$$
D
$$2BIr$$
2
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
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WB JEE 2021 Physics - Magnetism Question 11 English
Consider two infinitely long wires parallel to Z-axis carrying same current I in the positive z-direction. One wire passes through the point L at coordinates ($$-$$1, +1) and the other wire passes through the point M at coordinates ($$-$$1, $$-$$1). The resultant magnetic field at the origin O will be
A
$${{{\mu _0}I} \over {2\sqrt 2 \pi }}\widehat j$$
B
$${{{\mu _0}I} \over {2\pi }}\widehat j$$
C
$${{{\mu _0}I} \over {2\sqrt 2 \pi }}\widehat i$$
D
$${{{\mu _0}I} \over {4\pi }}\widehat i$$
3
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
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A thin charged rod is bent into the shape of a small circle of radius R, the charge per unit length of the rod being $$\lambda$$. The circle is rotated about its axis with a time period T and it is found the magnetic field at a distance d away (d >> R) from the centre and on the axis, varies as $$R^m \over d^n$$. The values of m and n respectively are
A
m = 2, n = 2
B
m = 2, n = 3
C
m = 3, n = 2
D
m = 3, n = 3
4
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
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WB JEE 2021 Physics - Magnetism Question 9 English
For two types of magnetic materials A and B, variation of $$1\over\chi$$ ($$\chi$$ : susceptibility) versus temperature T is shown in the figure. Then,
A
A is diamagnetic and B is paramagnetic.
B
A is feromagnetic and B is diamagnetic.
C
A is paramagnetic and B is feromagnetic.
D
A is paramagnetic and B is diamagnetic.
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