Exercise $2\mathrm{.}1$

An engine producing excess heat is passively cooled by addition

of pin fins to its casing. The fins are made of copper of $0\mathrm{.}35$ cm

diameter, extending from the wall at $100C$ into ambient air at

$30C$; h is $10\frac{W}{m^2}K.$ Calculate the heat loss assuming that

Fin is infinitely long;

fin $(3$ cm long$)$ is insulated at the tip;

fin is $3$ cm long and h is same as around the circumference.

$(k$ of copper $=396\frac{W}{m}K)$