Question

What is the charge induced in coil of 100 turns of
resistance 100 ohm, if magnetic flux changes from
2 T m2 to - 2 T m2??
(1) 4C
(2) 2 C
(3) 2.8 C
(4) 0.4 C
​

Answer 1

Answer:

R=100 ohm

N= 100

dφ=4

induced current i= e/r

induced emf= dφ/dt

q induced = i t = i * dt = dφ/r

= 4/100 * 100= 4C

Answer 2

Given:

• Resistance = 100 ohm
• Magnetic flux changes from 2 Tm² to -2 Tm².
• Number of turns = 100

To find:

• Induced current ?

Calculation:

According to Faraday's Law of Electromagnetic Induction, The induced EMF is equal to the rate of change of magnetic flux.

$EMF = - \dfrac{\Delta \phi}{\Delta t} \times n$

• Now, the value of induced current will be:

$\implies i= \dfrac{ - \dfrac{\Delta \phi}{\Delta t} \times n}{r}$

• Now, the charge induced will be:

$\implies q= \dfrac{ - \dfrac{\Delta \phi}{\Delta t} \times n}{r} \times \Delta t$

$\implies q= - \dfrac{ \bigg(- 2 - 2 \bigg) \times 100}{100}$

$\implies q= - \bigg( - 2 - 2\bigg)$

$\implies q= - ( - 4)$

$\implies q= 4 \: C$

So, value of induced charge is 4 C