An antenna in free space receives $2 \; \mu \mathrm{W}$ of power when the incident electric field is $20 \mathrm{~m} \; \mathrm{V} / \mathrm{m} \; \mathrm{rms}$. The effective aperture of the antenna is
- $0.005 \mathrm{~m}^{2}$
- $0.05 \mathrm{~m}^{2}$
- $1.885 \mathrm{~m}^{2}$
- $3.77 \mathrm{~m}^{2}$