The strength of the magnetic field produced by a current-carrying wire at a distance r from the wire is
[tex]B(r)= \frac{\mu_0 I}{2 \pi r} [/tex]
where I is the current in the wire.
From the equation, we see that the strength of the field is directly proportional to the current intensity, I. In the problem, the current is increased from 10 A to 25 A, so by a factor
[tex] \frac{I_2}{I_1}= \frac{25 A}{10 A}=2.5 [/tex]
therefore, the strength of the magnetic field will increase by the same factor:
[tex]B_2 = 2.5 B_1 = 2.5 (0.50 G)=1.25 G[/tex]
And the strength of the new magnetic field is 1.25 G.
