1
JEE Main 2019 (Online) 8th April Morning Slot
+4
-1
A 20 Henry inductor coil is connected to a 10 ohm resistance in series as shown in figure. The time at which rate of dissipation of energy (joule's heat) across resistance is equal to the rate at which magnetic energy is stored in the inductor is :
A
$${2 \over {\ln 2}}$$
B
$${\ln 2}$$
C
$$2{\ln 2}$$
D
$${1 \over 2}{\ln 2}$$
2
JEE Main 2019 (Online) 12th January Evening Slot
+4
-1
A 10 m long horizontal wire extends from North East to South West. It is falling with a speed of 5.0 ms–1, at right angles to the horizontal component of the earth's magnetic field of 0.3 $$\times$$ 10–4 Wb/m2. The value of the induced emf in wire is :
A
0.3 $$\times$$ 10–3 V
B
2.5 $$\times$$ 10–3 V
C
1.5 $$\times$$ 10–3 V
D
1.1 $$\times$$ 10–3 V
3
JEE Main 2019 (Online) 11th January Evening Slot
+4
-1
A copper wire is wound on a wooden frame, whose shape is that of an equilateral triangle. If the linear dimension of each side of the frame is increased by a factor of 3, keeping the number of turns of the coil per unit length of the frame the same, then the self inductance of the coil:
A
decreases by a factor of $$9\sqrt 3$$
B
increases by a factor of 27
C
decreases by a factor of 9
D
increases by a factor of 3
4
JEE Main 2019 (Online) 11th January Morning Slot
+4
-1
There are two long co-axial solenoids of same length $$l$$. The inner and outer coils have radii r1 and r2 and number of turns per unit length n1 and n2, respectively. The ratio of mutual inductance to the self - inductance of the inner-coil is :
A
$${{{n_2}} \over {{n_1}}}.{{{r_2}^2} \over {{r_1}^2}}$$
B
$${{{n_2}} \over {{n_1}}}$$
C
$${{{n_1}} \over {{n_2}}}$$
D
$${{{n_2}} \over {{n_1}}}.{{{r_1}} \over {{r_2}}}$$
EXAM MAP
Medical
NEET