Question

A fin is given with efficiency of 56%, the diameter of the fin is 25 cm. Effectiveness of the fin is also given as 3. Cal culate the total surface area of the fin. (assuming insulated tip) (A) 2629.68 cm (B) 2914.13 cm2 (C) 3495.06 cm (D)1508.09 cm

Answer 1

Answer:

(A) As≅ 2629.68 cm²

Explanation:

Given that

Efficiency ,η= 56 %

Effectiveness = 3

diameter,d = 25 cm

We know that

$\dfrac{\eta_{fin}}{\varepsilon _{fin}}=\dfrac{A_c}{A_s}$

Ac= Cross sectional area

As= Surface area

The cross sectional area Ac

Ac=πd²/4

Ac= πx 25²/4 cm²

Ac=490.62 cm²

$\dfrac{\eta_{fin}}{\varepsilon _{fin}}=\dfrac{A_c}{A_s}$

$\dfrac{0.56}{3}=\dfrac{490.62}{A_s}$

As=2628.34  cm²

As≅ 2629.68 cm²