15) A single fin protrudes from a plate as shown in the image below. The fin is 25 mm tall, 75 mm deep, and 1 mm thick. The fin has a thermal conductivity of 250 W/(m·K). The fin is exposed to a heat transfer coefficient of 100 W/(m²·K). A) What is the efficiency of the fin? B) What is the thermal resistance of the fin? C) EXTRA CREDIT (10 POINTS) Using the same VOLUME of material but forming the fin as an isosceles triangle with the same base thickness (i.e. 1 mm) and depth (i.e. 75 mm), is this fin "better"? Words are good but for full extra credit you need to put some numbers on this.

Fig: 1