Answer:
(a) 1.63 m
(b) 9.01 Wb
Step-by-step explanation:
Parameters given:
Magnetic field, B = 0.27 T
(a) Magnetic flux is the product of magnetic field and Area of a coil. It is given mathematically as:
∅ = BA
where A = area of coil =

=> ∅ = B

Making r subject of formula, we have:
= ∅/(Bπ)
When ∅ = 2.25 Wb:
=

=

=

(b) If the radius is doubled, r = 1.63 * 2 = 3.26 m. Then, the magnetic flux will be:
∅ = BA = B

∅ = 0.27 * π *

∅ = 9.01 Wb