1
JEE Main 2020 (Online) 5th September Evening Slot
+4
-1
An infinitely long, straight wire carrying current I, one side opened rectangular loop and a conductor C with a sliding connector are located in the same plane, as shown, in the figure. The connector has length $$l$$ and resistance R. It slides to the right with a velocity v. The resistance of the conductor and the self inductance of the loop are negligible. The induced current in the loop, as a function of separation r, between the connector and the straight wire is :
A
$${{{\mu _0}} \over {4\pi }}{{Ivl} \over {Rr}}$$
B
$${{{\mu _0}} \over {\pi }}{{Ivl} \over {Rr}}$$
C
$${{{\mu _0}} \over {2\pi }}{{Ivl} \over {Rr}}$$
D
$${{2{\mu _0}} \over \pi }{{Ivl} \over {Rr}}$$
2
JEE Main 2020 (Online) 4th September Morning Slot
+4
-1
A small bar magnet is moved through a coil at constant speed from one end to the other. Which of the following series of observations will be seen on the galvanometer G attached across the coil?
Three positions shown describe :
(a) the magnet's entry
(b) magnet is completely inside and
(c) magnet's exit.
A
B
C
D
3
JEE Main 2020 (Online) 3rd September Evening Slot
+4
-1
A uniform magnetic field B exists in a direction perpendicular to the plane of a square loop made of a metal wire. The wire has a diameter of 4 mm and a total length of 30 cm. The magnetic field changes with time at a steady rate $${{dB} \over {dt}}$$ = 0.032 Ts–1. The induced current in the loop is close to (Resistivity of the metal wire is 1.23 $$\times$$ 10–8 $$\Omega$$m)
A
0.53 A
B
0.43 A
C
0.34 A
D
0.61 A
4
JEE Main 2020 (Online) 3rd September Morning Slot
+4
-1
An elliptical loop having resistance R, of semi major axis a, and semi minor axis b is placed in magnetic field as shown in the figure. If the loop is rotated about the x-axis with angular frequency $$\omega$$, the average power loss in the loop due to Joule heating is :
A
$${{\pi abB\omega } \over R}$$
B
$${{{\pi ^2}{a^2}{b^2}{B^2}{\omega ^2}} \over R}$$
C
$${{{\pi ^2}{a^2}{b^2}{B^2}{\omega ^2}} \over {2R}}$$
D
Zero
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