(i) The direction of the current will be in opposite direction to the magnetic field.
(ii) The magnitude of the emf induced in the circuit is 0.359 V.
(iii) The induced current if the circular coil is 0.048 A.
b(i) The magnetic flux linkage through the coil is 1.41 x 10⁻⁴ Tm².
b(ii) The radius of the coil is r√3 m.
<h3>
Direction of the current</h3>
The direction of the current will be in opposite direction to the magnetic field.
<h3>Emf induced in the circuit</h3>
Initial area of the coil = (πd²)/4
Initial area of the coil = (π x 0.225²)/4 = 0.0398 m²
Final area of the coil = (π x 0.072²)/4 = 0.001296 m²
![emf = \frac{NB(A_1 - A_2)}{t} \\\\emf = \frac{14 \times 1.2(0.0398 - 0.001296)}{1.8} \\\\emf = 0.359 \ V](https://tex.z-dn.net/?f=emf%20%3D%20%5Cfrac%7BNB%28A_1%20-%20A_2%29%7D%7Bt%7D%20%5C%5C%5C%5Cemf%20%3D%20%5Cfrac%7B14%20%5Ctimes%201.2%280.0398%20-%200.001296%29%7D%7B1.8%7D%20%5C%5C%5C%5Cemf%20%3D%200.359%20%5C%20V)
<h3>Induced current</h3>
I = emf/R
I = 0.359/7.5
I = 0.048 A
<h3>Magnetic flux linkage through the coil</h3>
Ф = LI
Ф = 0.015 x 0.0094
Ф = 1.41 x 10⁻⁴ Tm²
<h3>Radius of the coil</h3>
![L = \frac{\mu_o N^2\pi r^2}{l} \\\\r^2 = \frac{Ll}{\mu_o N^2\pi } \\\\r = \sqrt{\frac{Ll}{\mu_o N^2\pi } } \\\\r = \sqrt{\frac{0.015(l)}{4\pi\times 10^{-7} \times (420)^2 \pi } } \\\\r = 3 \sqrt{l} \ m](https://tex.z-dn.net/?f=L%20%3D%20%5Cfrac%7B%5Cmu_o%20N%5E2%5Cpi%20r%5E2%7D%7Bl%7D%20%5C%5C%5C%5Cr%5E2%20%3D%20%5Cfrac%7BLl%7D%7B%5Cmu_o%20N%5E2%5Cpi%20%7D%20%5C%5C%5C%5Cr%20%3D%20%5Csqrt%7B%5Cfrac%7BLl%7D%7B%5Cmu_o%20N%5E2%5Cpi%20%7D%20%7D%20%5C%5C%5C%5Cr%20%3D%20%20%5Csqrt%7B%5Cfrac%7B0.015%28l%29%7D%7B4%5Cpi%5Ctimes%2010%5E%7B-7%7D%20%5Ctimes%20%28420%29%5E2%20%5Cpi%20%7D%20%7D%20%5C%5C%5C%5Cr%20%3D%203%20%5Csqrt%7Bl%7D%20%5C%20m)
where;
Learn more about inductance of coil here: brainly.com/question/17086348