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diff --git a/1309/CH7/EX7.9/ch7_9.sce b/1309/CH7/EX7.9/ch7_9.sce
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+clc;
+clear;
+printf("\t\t\tChapter7_example9\n\n\n");
+// determination of required current
+// properties of air at film temperature (300 + 500)/2 = 400 K from appendix table D1
+rou= 0.883; // density in kg/cu.m
+cp= 1014; // specific heat in J/(kg*K) 
+v= 25.90e-6; // viscosity in sq.m/s  
+Pr = 0.689; // Prandtl Number 
+kf= 0.03365; // thermal conductivity in W/(m.K)
+a = 0.376e-4; // diffusivity in sq.m/s
+V_inf=1; // velocity in m/s
+D=0.00013; // diameter in m
+L=1/100; // length of wire in cm
+Re_D=V_inf*D/v; // The Reynolds number of flow past the wire
+printf("\nThe Reynolds number of flow past the wire is %.3f",Re_D);
+C=0.911; //value of C for cylinder from table 7.4
+m=0.385; //value of m for cylinder from table 7.4
+hc=kf*C*(Re_D)^m*(Pr)^(1/3)/D; // the convection coefficient in W/(m^2.K)
+printf("\nThe convection coefficient is %d W/(sq.m.K)",hc);
+Tw=500; // air stream temperature in K
+T_inf=300; // wire surface temperature in K
+As=%pi*D*L; // cross sectional area in sq.m
+qw=hc*As*(Tw-T_inf); // The heat transferred to the air from the wire
+printf("\nThe heat transferred to the air from the wire is %.3f W",qw);
+resistivity=17e-6; // resistivity in ohm cm
+Resistance=resistivity*(L/(%pi*D^2)); // resistance in ohm
+printf("\nThe resistance is %.3f ohm",Resistance/100);
+i=(qw*100/Resistance)^0.5; // current in ampere
+printf("\nThe current is %.1f A",i);