The minimum frequency for a radio to tune is given as $v_{1}=7.5 M H z=7.5 \times 10^{6} H z$

$=\frac{3 \times 10^{3}}{7.5 \times 10^{8}}=40 \mathrm{~m}$

$\lambda_{2}=\frac{c}{v_{2}}$

$=\frac{3 \times 10^{3}}{12 \times 10^{\circ}}=25 \mathrm{~m}$

Thus, $40 \mathrm{~m}$ to $25 \mathrm{~m}$ is the wavelength band of the radio.