This is a magnetic dipole. A magnetic dipole in a vacuum radiates an average power by the following relation.
`ltPgt =(mu_0 m_0^2 omega^4)/(12 pi c^3)`
`mu_0` is the magnetic permeability of a vacuum, `m_0` is the average magnetic dipole moment, omega is the angular frequency, and `c` is the speed of light.
First we know that `m_0=Ia` , where `I` is the current and a is the area of the loop. We want to know `(< P_f >) / (< P_i >)` .
`(<P_f>)/(<P_i>)=(mu_0 I_f^2 a^2 omega_f^4)/(12 pi c^3)*(12 pi c^3)/(mu_0 I_i^2 a^2 omega_i^4)=(I_f omega_f^4)/(I_i omega_i^4)`
Plug in the changes between the final and initial configurations.
`(<P_f>)/(<P_i>)=(I_f^2 omega_f^4)/(I_i^2 omega_i^4)=((2I_i)^2 (2omega_i)^4)/(I_i^2 omega_i^4)=2^6`
The antenna radiates `2^6` times more power than initially.
See eNotes Ad-Free
Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.
Already a member? Log in here.