1
JEE Main 2019 (Online) 8th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Two very long, straight, and insulated wires are kept at 90° angle from each other in xy-plane as shown in the figure. These wires carry currents of equal magnitude I, whose directions are shown in the figure. The net magnetic field at point P will be : JEE Main 2019 (Online) 8th April Evening Slot Physics - Magnetic Effect of Current Question 165 English
A
$${{ + {\mu _0}I} \over {\pi d}}\left( {\mathop z\limits^ \wedge } \right)$$
B
$$ - {{{\mu _0}I} \over {2\pi d}}\left( {\mathop x\limits^ \wedge + \mathop y\limits^ \wedge } \right)$$
C
Zero
D
$$ {{{\mu _0}I} \over {2\pi d}}\left( {\mathop x\limits^ \wedge + \mathop y\limits^ \wedge } \right)$$
2
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A thin strip 10 cm long is on a U shaped wire of negligible resistance and it is connected to a spring of spring constant 0.5 Nm–1 (see figure). The assembly is kept in a uniform magnetic field of 0.1 T. If the strip is pulled from its equilibrium position and released, the number of oscillation it performs before its amplitude decreases by a factor of e is N. If the mass of the strip is 50 grams, its resistance 10W and air drag negligible, N will be close to : JEE Main 2019 (Online) 8th April Morning Slot Physics - Magnetic Effect of Current Question 166 English
A
50000
B
1000
C
5000
D
10000
3
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A circular coil having N turns and radius r carries a current I. It is held in the XZ plane in a magnetic field B$${\mathop i\limits^ \wedge }$$ . The torque on the coil due to the magnetic field is :
A
$${{B{r^2}I} \over {\pi N}}$$
B
B$$\pi $$r2IN
C
Zero
D
$${{B\pi{r^2}I} \over { N}}$$
4
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A proton and an $$\alpha $$-particle (with their masses in the ratio of 1 : 4 and charges in the ratio of 1 : 2) are accelerated from rest through a potential difference V. If a uniform magnetic field (B) is set up perpendicular to their velocities, the ratio of the radii rp : r$$\alpha $$ of the circular paths described by them will be ;
A
$$1:\sqrt 3 $$
B
1 : 3
C
$$1:\sqrt 2 $$
D
1 : 2
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