At what efficiency is a photovoltaic array running if insolation on the collector is \(650 \mathrm{~W} / \mathrm{m}^{2}\), the total collector area is \(10 \mathrm{~m}^{2}\), the voltage across the array is \(50 \mathrm{~V}\), and the current being delivered is \(15 \mathrm{~A}\) ?