Explanation:
The magnetic field at the center of the wire is given by :
[tex]B=\dfrac{\mu_oI}{2r}[/tex]
Here,
I is current flowing throgh the loop
r is the radius of loop
If the radius of the wire is doubled and the current is tripled, then new magnetic field is given by :
[tex]B'=\dfrac{\mu_oI'}{2r'}\\\\B'=\dfrac{\mu_o(3I)}{2(2r)}\\\\B'=\dfrac{3}{2}\times \dfrac{\mu_oI}{2r}\\\\B'=\dfrac{3}{2}\times B[/tex]
So, the new value of magnetic field gets 3/2th of the initial magnetic field.