1
JEE Main 2015 (Offline)
+4
-1
Two coaxial solenoids of different radius carry current $$I$$ in the same direction. $$\overrightarrow {{F_1}}$$ be the magnetic force on the inner solenoid due to the outer one and $$\overrightarrow {{F_2}}$$ be the magnetic force on the outer solenoid due to the inner one. Then :
A
$$\overrightarrow {{F_1}}$$ is radially in wards and $$\overrightarrow {{F_2}} = 0$$
B
$$\overrightarrow {{F_1}}$$ is radially outwards and $$\overrightarrow {{F_2}} = 0$$
C
$$\overrightarrow {{F_1}} = \overrightarrow {{F_2}} = 0$$
D
$$\overrightarrow {{F_1}}$$ is radially inwards and $$\overrightarrow {{F_2}}$$ is radially outards
2
JEE Main 2013 (Offline)
+4
-1
A circular loop of radius $$0.3$$ $$cm$$ lies center of the small loop is on the axis of the bigger loop. The distance between their centers is $$15$$ $$cm.$$ If a current of $$2.0$$ $$A$$ flows through the smaller loop, than the flux linked with bigger loop is
A
$$9.1 \times {10^{ - 11}}\,$$ weber
B
$$6 \times {10^{ - 11}}\,$$ weber
C
$$3.3 \times {10^{ - 11}}\,$$ weber
D
$$6.6 \times {10^{ - 9}}\,$$ weber
3
JEE Main 2013 (Offline)
+4
-1
A metallic rod of length $$'\ell '$$ is tied to a string of length $$2$$$$\ell$$ and made to rotate with angular speed $$w$$ on a horizontal table with one end of the string fixed. If there is a vertical magnetic field $$'B'$$ in the region, the $$e.m.f$$ induced across the ends of the rod is
A
$${{2B\omega \ell } \over 2}$$
B
$${{3B\omega \ell } \over 2}$$
C
$${{4B\omega {\ell ^2}} \over 2}$$
D
$${{5B\omega {\ell ^2}} \over 2}$$
4
AIEEE 2012
+4
-1
A coil is suspended in a uniform magnetic field, with the plane of the coil parallel to the magnetic lines of force. When a current is passed through the coil it starts oscillating; It is very difficult to stop. But if an aluminium plate is placed near to the coil, it stops. This is due to :
A
development of air current when the plate is placed
B
induction of electrical charge on the plate
C
shielding of magnetic lines of force as aluminium is a para-magnetic material.
D
electromagnetic induction in the aluminium plate giving rise to electromagnetic damping.
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