1. A meteorological instrument is suspended by fine wires in a cubical box with a side length of 20 cm. The box is mounted on a post, so all six sides of the box are exposed to the wind. The walls of the box are 2 mm thick and made of plastic with a conductivity of 0.5 W/mK. The instrument dissipates 15 W of electrical power. The average convective heat transfer coefficient on the outer surface of the box is 50 W/mK. The convective heat transfer coefficient on the inside surface of the box and on the surface of the instrument is 10 W/mK. The instrument has a surface area of 0.06 m. What is the temperature difference between surface temperature of the instrument and the outside air temperature? (2 points)