One advantage of using a Fresnel plastic lens over that of a standard quartz convex lens of the same focal length is

The radiation of the fire causes the saucepan to heat up. the conduction of the saucepan then to distribute the heat over the saucepan and to give heat to the water. the convection of the water distributing the heat within the water, till all the water is boiling

490 n  f=125n a=2.5m/s2

Answer ( slope);