Question

Magnetic flux in a circular coil of resistance $10\Omega$ changes with the time as shown in the figure. Magnetic field direction is perpendicular to paper inwards. Match the following:

Table 1 Table 2

(a) At 1s is induced current is	(p) clock wise
(b) At 5 s induced current is	(q) anticlockwise
(c) At 9s is induced current is	(r) zero
(d) At 15 s induced current is	(s) 2A (t) None

• A. a-q; b-r; c-p; d-q
• B. a-p; b-r; c-q; d-p
• C. a-r; b-p; c-q; d-r
• D. a-p; b-r; c-s; d-q

Answer 1

The correct option is A a-q; b-r; c-p; d-q

$t=1sec,\frac{d\Phi }{dt}=\frac{10}{2}=5,i=\frac{5}{10}=.05A,$ +ve flux therefore anti clockwise current
$t=5s,\frac{d\Phi }{dt}=0,i=0$
$t=9s,\frac{d\Phi }{dt}=\frac{10+10}{6-10}=-5,i=-0.5A,$ i.e. clockwise current
$t=15s,\frac{d\Phi }{dt}=\frac{10}{2}=5,i=0.5A,$ i.e. anti clockwise