Solar cells are given antireflection coatings to maximize their efficiency. Consider a silicon solar cell (n=3.50$n\phantom{\rule{thickmathspace}{0ex}}=\phantom{\rule{thickmathspace}{0ex}}3.50$) coated with a layer of silicon dioxide (n=1.45$n\phantom{\rule{thickmathspace}{0ex}}=\phantom{\rule{thickmathspace}{0ex}}1.45$).

What is the minimum coating thickness (but not zero) that will minimize the reflection at the wavelength of 704 nm$\phantom{\rule{thickmathspace}{0ex}}\mathrm{n}\mathrm{m}$ where solar cells are most efficient?