Question

A heart pacing device consists of a coil of 50 turns and radius 1mm just inside the body with a coil of 1000 turns and radius 2 cm placed concentrically and co-axially just outside the body. Calculate the average induced EMF in the internal coil, if a current of 1A in the external coil collapses in 10 milliseconds.

• A. 493 $\mu V$
• B. 986 $\mu V$
• C. 493 m V
• D. 986 mV

Answer 1

The correct option is A

493 $\mu V$

$B=\frac{{\mu }_0{n}_0{I}_0}{2R_0}and\varphi =n_i\pi r_1^{2}BEMF=-\frac{\Delta \varphi }{\Delta t}=-\frac{n_0{\mu }_0\pi r_i^2{n}_i}{2R_0}\times \frac{\Delta I}{\Delta t}=493\mu V$