A positively charged object with a mass of 0.115 kg oscillates at the end of a spring,

Question:

A positively charged object with a mass of 0.115 kg oscillates at the end of a spring, generating ELF (extremely low frequency) radio waves that have a wavelength of 4.80 × 107 m. The frequency of these radio waves is the same as the frequency at which the object oscillates. What is the spring constant of the spring?