Question

Computers store memory by spinning a stack of magnetic-coated plates beneath an electromagnetic head. Suppose a head consists of a 148-turn coil wrapped around an iron ring with an area of 1.25 × 10-8 m2. The head is parallel to a magnetic field that changes by 5.2 × 10-4 T in 8.5 × 10-9 s. What is the induced emf in the coil?

Computers store memory by spinning a stack of magnetic-coated plates beneath an electromagnetic head. Suppose a head consists of a 148-turn coil wrapped around an iron ring with an area of 1.25 × 10^-8 m2. The head is parallel to a magnetic field that changes by 5.2 × 10^-4 T in 8.5 × 10^-9 s. What is the induced emf in the coil?

Answer 1

Solution

The induced e.m.f. is given by,

Where phi_B is the magnetic flux through the loop. For a finite change in magnetic field within a finite time this can be also written as,

Here change in magnetic flux is given by,

And given time interval,

Thus induced e.m.f,

Thus induced e.m.f in the loop is ​​​​​​​113.18mV