|
Q8: Wire coil parallel to changing magnetic field
A 100-turn wire coil has a resistance of 400 Ω and a cross-sectional area of `0.01 m^2`. The coil is placed in a magnetic field directed parallel to the axis of the coil. If the field changes at a rate of `-0.4 T//s`, what is the current induced in the coil?
The flux `ø_B = BA`
`=>`
`(∆ø_B)/(∆t) = (∆B)/(∆t)A`
`(∆ø_B)/(∆t) = (-0.4 T//s)(0.01 m^2) = -4.0 × 10^-3 Wb//s`
The emf induced in 100-loop coil:
`ℰ = -N(∆ø_B)/(∆t) = -(100)(-4.0 × 10^-3 Wb//s) = 0.4 V`
`I = ℰ /R = (0.4 V)/(400 Ω) = 1 × 10^-3 A`
|

Share: