Discussion Forum

1)

In a coil of resistance 100 Ω, a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is 

Answer:

Option B

Explanation:

Induced constant . $I= \frac{e}{R}$

 Here, e= induced emf

 $= \frac{d\phi}{dt}$

 $I=\frac{e}{R}= (\frac{d\phi}{dt}).\frac{1}{R}$

 $d\phi=IRdt$

 $\phi =\int_{}^{} IRdt$

 $\therefore$   Here, R is constant

  $\therefore$     $\phi =R\int_{}^{} Idt$

$\int_{}^{} I.dt =$  Area under I- t graph

 = $\frac{1}{2}\times 10 \times 0.5 =2.5$

 $\therefore$     $\phi =R\times 25$

                          = 100 × 2.5

                          =250 Wb