1
JEE Main 2021 (Online) 26th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The fractional change in the magnetic field intensity at a distance 'r' from centre on the axis of current carrying coil of radius 'a' to the magnetic field intensity at the centre of the same coil is : (Take r < a)
A
$${3 \over 2}{{{a^2}} \over {{r^2}}}$$
B
$${2 \over 3}{{{a^2}} \over {{r^2}}}$$
C
$${2 \over 3}{{{r^2}} \over {{a^2}}}$$
D
$${3 \over 2}{{{r^2}} \over {{a^2}}}$$
2
JEE Main 2021 (Online) 27th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Figure A and B shown to long straight wires of circular cross-section (a and b with a < b), carrying current I which is uniformly distributed across the cross-section. The magnitude of magnetic field B varies with radius r and can be represented as :

JEE Main 2021 (Online) 27th July Evening Shift Physics - Magnetic Effect of Current Question 83 English
A
JEE Main 2021 (Online) 27th July Evening Shift Physics - Magnetic Effect of Current Question 83 English Option 1
B
JEE Main 2021 (Online) 27th July Evening Shift Physics - Magnetic Effect of Current Question 83 English Option 2
C
JEE Main 2021 (Online) 27th July Evening Shift Physics - Magnetic Effect of Current Question 83 English Option 3
D
JEE Main 2021 (Online) 27th July Evening Shift Physics - Magnetic Effect of Current Question 83 English Option 4
3
JEE Main 2021 (Online) 25th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Two ions having same mass have charges in the ratio 1 : 2. They are projected normally in a uniform magnetic field with their speeds in the ratio 2 : 3. The ratio of the radii of their circular trajectories is :
A
1 : 4
B
4 : 3
C
3 : 1
D
2 : 3
4
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
A deuteron and an alpha particle having equal kinetic energy enter perpendicularly into a magnetic field. Let rd and r$$\alpha$$ be their respective radii of circular path. The value of $${{{r_d}} \over {{r_\alpha }}}$$ is equal to :
A
1
B
2
C
$$\sqrt 2 $$
D
$${1 \over {\sqrt 2 }}$$
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