From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001
From: priyanka
Date: Wed, 24 Jun 2015 15:03:17 +0530
Subject: initial commit / add all books

---
 1826/CH2/EX2.13/ex2_13.sce  |  26 ++++++++++++++++++++++++++
 1826/CH2/EX2.15/ex2_15.sce  |   9 +++++++++
 1826/CH2/EX2.16/ex2_16.sce  |   8 ++++++++
 1826/CH2/EX2.17/ex2_17.sce  |   7 +++++++
 1826/CH2/EX2.18/ex2_18.sce  |  13 +++++++++++++
 1826/CH2/EX2.19/ex2_19.sce  |  12 ++++++++++++
 1826/CH2/EX2.2/ex2_2.sce    |  11 +++++++++++
 1826/CH2/EX2.20/ex2_20.sce  |  11 +++++++++++
 1826/CH2/EX2.22/ex2_22.sce  |  12 ++++++++++++
 1826/CH2/EX2.23/ex2_23.sce  |  13 +++++++++++++
 1826/CH2/EX2.24/ex2_24.jpg  | Bin 0 -> 211959 bytes
 1826/CH2/EX2.24/ex2_24.sce  |  24 ++++++++++++++++++++++++
 1826/CH2/EX2.24/ex2_24c.jpg | Bin 0 -> 79445 bytes
 1826/CH2/EX2.25/ex2_25.sce  |   8 ++++++++
 1826/CH2/EX2.26/ex2_26.sce  |  13 +++++++++++++
 1826/CH2/EX2.27/ex2_27.sce  |  10 ++++++++++
 1826/CH2/EX2.28/ex2_28.sce  |  12 ++++++++++++
 1826/CH2/EX2.29/ex2_29.sce  |  10 ++++++++++
 1826/CH2/EX2.3/ex2_3.sce    |  11 +++++++++++
 1826/CH2/EX2.30/ex2_30.sce  |  10 ++++++++++
 1826/CH2/EX2.31/ex2_31.sce  |   8 ++++++++
 1826/CH2/EX2.32/ex2_32.sce  |  12 ++++++++++++
 1826/CH2/EX2.35/ex2_35.sce  |  13 +++++++++++++
 1826/CH2/EX2.36/ex2_36.sce  |  11 +++++++++++
 1826/CH2/EX2.38/ex2_38.sce  |   4 ++++
 1826/CH2/EX2.4/ex2_4.sce    |  11 +++++++++++
 1826/CH2/EX2.5/ex2_5.sce    |  10 ++++++++++
 1826/CH2/EX2.6/ex2_6.sce    |   9 +++++++++
 1826/CH2/EX2.7/ex2_7.sce    |   9 +++++++++
 1826/CH2/EX2.8/ex2_8.sce    |  17 +++++++++++++++++
 1826/CH2/EX20.21/ex2_21.sce |   9 +++++++++
 31 files changed, 333 insertions(+)
 create mode 100755 1826/CH2/EX2.13/ex2_13.sce
 create mode 100755 1826/CH2/EX2.15/ex2_15.sce
 create mode 100755 1826/CH2/EX2.16/ex2_16.sce
 create mode 100755 1826/CH2/EX2.17/ex2_17.sce
 create mode 100755 1826/CH2/EX2.18/ex2_18.sce
 create mode 100755 1826/CH2/EX2.19/ex2_19.sce
 create mode 100755 1826/CH2/EX2.2/ex2_2.sce
 create mode 100755 1826/CH2/EX2.20/ex2_20.sce
 create mode 100755 1826/CH2/EX2.22/ex2_22.sce
 create mode 100755 1826/CH2/EX2.23/ex2_23.sce
 create mode 100755 1826/CH2/EX2.24/ex2_24.jpg
 create mode 100755 1826/CH2/EX2.24/ex2_24.sce
 create mode 100755 1826/CH2/EX2.24/ex2_24c.jpg
 create mode 100755 1826/CH2/EX2.25/ex2_25.sce
 create mode 100755 1826/CH2/EX2.26/ex2_26.sce
 create mode 100755 1826/CH2/EX2.27/ex2_27.sce
 create mode 100755 1826/CH2/EX2.28/ex2_28.sce
 create mode 100755 1826/CH2/EX2.29/ex2_29.sce
 create mode 100755 1826/CH2/EX2.3/ex2_3.sce
 create mode 100755 1826/CH2/EX2.30/ex2_30.sce
 create mode 100755 1826/CH2/EX2.31/ex2_31.sce
 create mode 100755 1826/CH2/EX2.32/ex2_32.sce
 create mode 100755 1826/CH2/EX2.35/ex2_35.sce
 create mode 100755 1826/CH2/EX2.36/ex2_36.sce
 create mode 100755 1826/CH2/EX2.38/ex2_38.sce
 create mode 100755 1826/CH2/EX2.4/ex2_4.sce
 create mode 100755 1826/CH2/EX2.5/ex2_5.sce
 create mode 100755 1826/CH2/EX2.6/ex2_6.sce
 create mode 100755 1826/CH2/EX2.7/ex2_7.sce
 create mode 100755 1826/CH2/EX2.8/ex2_8.sce
 create mode 100755 1826/CH2/EX20.21/ex2_21.sce

(limited to '1826/CH2')

diff --git a/1826/CH2/EX2.13/ex2_13.sce b/1826/CH2/EX2.13/ex2_13.sce
new file mode 100755
index 000000000..4379df466
--- /dev/null
+++ b/1826/CH2/EX2.13/ex2_13.sce
@@ -0,0 +1,26 @@
+// Example 2.13, page no-37
+clear
+clc
+//(i)
+h=1
+k=1
+l=1
+a=4.12*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("\nFor (111) plane\nThe lattice spacing is %.3f*10^-10 m",d*10^10)
+//(ii)
+
+h=1
+k=1
+l=2
+a=4.12*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("\n\nFor (112) plane\nThe lattice spacing is %.3f*10^-10 m",d*10^10)
+//(iii)
+
+h=1
+k=2
+l=3
+a=4.12*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("\n\nFor (123) plane\nThe lattice spacing is %.3f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.15/ex2_15.sce b/1826/CH2/EX2.15/ex2_15.sce
new file mode 100755
index 000000000..e44b94481
--- /dev/null
+++ b/1826/CH2/EX2.15/ex2_15.sce
@@ -0,0 +1,9 @@
+// Example 2.15, page no-38
+clear
+clc
+h=2
+k=2
+l=0
+a=4.938*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("\nThe lattice spacing for (220) plane is %.3f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.16/ex2_16.sce b/1826/CH2/EX2.16/ex2_16.sce
new file mode 100755
index 000000000..4dd38e4c3
--- /dev/null
+++ b/1826/CH2/EX2.16/ex2_16.sce
@@ -0,0 +1,8 @@
+// Example 2.16, page no-39
+clear
+clc
+a=0.405*10^-10//m
+t=0.005//m
+A=25*10^-2//m
+n=t*A/a^3
+printf("The number of atoms in the Al foil is %.2f * 10^28",n*10^-28)
diff --git a/1826/CH2/EX2.17/ex2_17.sce b/1826/CH2/EX2.17/ex2_17.sce
new file mode 100755
index 000000000..554d79fa2
--- /dev/null
+++ b/1826/CH2/EX2.17/ex2_17.sce
@@ -0,0 +1,7 @@
+// Example 2.17, page no-39
+clear
+clc
+a=2.88*10^-10//
+d=7200//k/m^3
+n=1/(d*a^3)
+printf("The number of unit cell present in 1 kg metal is %.4f *10^24",n*10^-24)
diff --git a/1826/CH2/EX2.18/ex2_18.sce b/1826/CH2/EX2.18/ex2_18.sce
new file mode 100755
index 000000000..439ef6635
--- /dev/null
+++ b/1826/CH2/EX2.18/ex2_18.sce
@@ -0,0 +1,13 @@
+// Example 2.18, page no-39
+clear
+clc
+rbcc=0.1258*10^-9
+rfcc=0.1292*10^-9
+a=4*rbcc/sqrt(3)
+vbcc=(a^3)/2
+a1=4*rfcc/sqrt(2)
+vfcc=(a1^3)/4
+vp=(vbcc-vfcc)
+vp=floor(vp*10^32)
+vp=vp*10^-32/vbcc
+printf("The volume change in %% duringg the structural change is %.4f",vp*100)
diff --git a/1826/CH2/EX2.19/ex2_19.sce b/1826/CH2/EX2.19/ex2_19.sce
new file mode 100755
index 000000000..f2698e789
--- /dev/null
+++ b/1826/CH2/EX2.19/ex2_19.sce
@@ -0,0 +1,12 @@
+// Example 2.19, page no-40
+clear
+clc
+awt=63.5*10^-3//g
+avg=6.023*10^26
+r=1.273*10^-10
+n=4
+a=4*r/sqrt(2)
+d=n*awt/(avg*a^3)
+printf("The density of copper is %.4f gm/m^3",d)
+
+
diff --git a/1826/CH2/EX2.2/ex2_2.sce b/1826/CH2/EX2.2/ex2_2.sce
new file mode 100755
index 000000000..b62d0d362
--- /dev/null
+++ b/1826/CH2/EX2.2/ex2_2.sce
@@ -0,0 +1,11 @@
+// Example 2.2, page no-29
+clear
+clc
+// Intercepts are in the ratio 3a:4b along X,Y and parallel to Z axis
+//x intercept 3,y intercept 4 and z intercept infinity 
+a=2*10^-10// 2 Angstrom
+h=4
+k=3
+l=0
+d=a/sqrt(h^2+k^2+l^2)
+printf("The lattice spacing for the plane 430 is %.1f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.20/ex2_20.sce b/1826/CH2/EX2.20/ex2_20.sce
new file mode 100755
index 000000000..47e812867
--- /dev/null
+++ b/1826/CH2/EX2.20/ex2_20.sce
@@ -0,0 +1,11 @@
+// Example 2.20, page no-41
+clear
+clc
+d=7860
+m=55.85
+n=2
+avg=6.023*10^26
+a=(n*m*10^-3/(avg*d))^(1/3)
+r=a*sqrt(3)/4
+printf("\nThe lattice constant of alfa-iron is %.4f A°",a*10^10)
+printf("\nThe atomic radius  of alfa-iron is %.5f *10^-10 m",r*10^10)
diff --git a/1826/CH2/EX2.22/ex2_22.sce b/1826/CH2/EX2.22/ex2_22.sce
new file mode 100755
index 000000000..c2c555347
--- /dev/null
+++ b/1826/CH2/EX2.22/ex2_22.sce
@@ -0,0 +1,12 @@
+// Example 2.22, page no-42
+clear
+clc
+a=3.81*10^-10//m
+h=1
+k=3
+l=2
+lam=0.58*10^-10
+n=2
+d=a/sqrt(h^2+k^2+l^2)
+theta=asin(n*lam/(2*d))
+printf("The angle of glancing at which 2nd order diffraction pattern of NaCl occurs is %.2f°",theta*180/%pi)
diff --git a/1826/CH2/EX2.23/ex2_23.sce b/1826/CH2/EX2.23/ex2_23.sce
new file mode 100755
index 000000000..423554562
--- /dev/null
+++ b/1826/CH2/EX2.23/ex2_23.sce
@@ -0,0 +1,13 @@
+// Example 2.23, page no-43
+clear
+clc
+h=3
+k=0
+l=2
+theta=35//in degrees
+lam=0.7*10^-10//m
+n=1
+d=n*lam/(2*sin(theta*%pi/180))
+printf("\nThe interplanar distance for(302) plane is %.3f*10^-11 m",d*10^11)
+a=d*sqrt(h^2+k^2+l^2)
+printf("\nThe lattice constance is %.2f*10^-10 m",a*10^10)
diff --git a/1826/CH2/EX2.24/ex2_24.jpg b/1826/CH2/EX2.24/ex2_24.jpg
new file mode 100755
index 000000000..2e7ed2d57
Binary files /dev/null and b/1826/CH2/EX2.24/ex2_24.jpg differ
diff --git a/1826/CH2/EX2.24/ex2_24.sce b/1826/CH2/EX2.24/ex2_24.sce
new file mode 100755
index 000000000..297146193
--- /dev/null
+++ b/1826/CH2/EX2.24/ex2_24.sce
@@ -0,0 +1,24 @@
+// Example 2.24, page no-44
+clear
+clc
+///for plane (0,0,1)
+deff('z=f(x,y)','z=x^0-y^0')
+x=0:0.2:3 ;y=x ;
+//clf() ;
+subplot(311)
+fplot3d(x,y,f,alpha=5,theta=31)
+
+///For plane(1,0,1)
+deff('z=f(x,y)','z=x^1-y^0')
+x=0:0.2:3 ;y=x ;
+//clf() ;
+subplot(312)
+fplot3d(x,y,f,alpha=5,theta=31)
+
+///For plane(1,1,1)
+deff('z=f(x,y)','z=x^1-y^1')
+x=0:0.2:3 ;y=x ;
+//clf() ;
+subplot(313)
+fplot3d(x,y,f,alpha=5,theta=31)
+
diff --git a/1826/CH2/EX2.24/ex2_24c.jpg b/1826/CH2/EX2.24/ex2_24c.jpg
new file mode 100755
index 000000000..fd0ce6c5e
Binary files /dev/null and b/1826/CH2/EX2.24/ex2_24c.jpg differ
diff --git a/1826/CH2/EX2.25/ex2_25.sce b/1826/CH2/EX2.25/ex2_25.sce
new file mode 100755
index 000000000..22c78d294
--- /dev/null
+++ b/1826/CH2/EX2.25/ex2_25.sce
@@ -0,0 +1,8 @@
+// Example 2.25, page no-45
+clear
+clc
+theta=12//in degrees
+lam=2.82*10^-10//m
+n=1
+d=n*lam/(2*sin(theta*%pi/180))
+printf("The interplanar spacing is %.3f *10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.26/ex2_26.sce b/1826/CH2/EX2.26/ex2_26.sce
new file mode 100755
index 000000000..1ff572853
--- /dev/null
+++ b/1826/CH2/EX2.26/ex2_26.sce
@@ -0,0 +1,13 @@
+// Example 2.26, page no-46
+clear
+clc
+theta=27.5/2//in degrees
+a=0.563*10^-9
+n=1
+h=1
+k=1
+l=1
+d=a/sqrt(h^2+k^2+l^2)
+printf("\nThe lattice spacing for the plane (111) is %.2f * 10^-10 m",d*10^10)
+lam=2*d*sin(theta*%pi/180)/n
+printf("\nThe deBroglie wavelength of the neutrons is %.3f *10^-10 m",lam*10^10)
diff --git a/1826/CH2/EX2.27/ex2_27.sce b/1826/CH2/EX2.27/ex2_27.sce
new file mode 100755
index 000000000..d8964ac6f
--- /dev/null
+++ b/1826/CH2/EX2.27/ex2_27.sce
@@ -0,0 +1,10 @@
+// Example 2.27, page no-46
+clear
+clc
+h=1
+k=1
+l=0
+d=2*10^-10//m
+a=d*sqrt(h^2+k^2+l^2)
+R=a/(2*sqrt(2))
+printf("The lattice constant is %.3f*10^-10 m\nThe atomic radius of the crystal is %.1f *10^-10 m",a*10^10,R*10^10)
diff --git a/1826/CH2/EX2.28/ex2_28.sce b/1826/CH2/EX2.28/ex2_28.sce
new file mode 100755
index 000000000..b84a7d4de
--- /dev/null
+++ b/1826/CH2/EX2.28/ex2_28.sce
@@ -0,0 +1,12 @@
+// Example 2.28, page no-47
+clear
+clc
+theta=22//in degrees
+d=1.8*10^-10//m
+n=1
+h=6.626*10^-34
+m=9.1*10^-31//kg
+e=1.6*10^-19//C
+lam=2*d*sin(theta*%pi/180)/n
+E=(1/(2*m))*(h/lam)^(2)
+printf("\nThe deBroglie wavelength of the neutron is %.3f *10^-10\nthe energy of the neutron is %.2f eV",lam*10^10,E/e)
diff --git a/1826/CH2/EX2.29/ex2_29.sce b/1826/CH2/EX2.29/ex2_29.sce
new file mode 100755
index 000000000..edc6bff85
--- /dev/null
+++ b/1826/CH2/EX2.29/ex2_29.sce
@@ -0,0 +1,10 @@
+// Example 2.29, page no-48
+clear
+clc
+
+h=1
+k=1
+l=1
+a=3*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("\nThe interplanar spacing for the plane(101) is %.3f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.3/ex2_3.sce b/1826/CH2/EX2.3/ex2_3.sce
new file mode 100755
index 000000000..8800ef2c7
--- /dev/null
+++ b/1826/CH2/EX2.3/ex2_3.sce
@@ -0,0 +1,11 @@
+// Example 2.3, page no-31
+clear
+clc
+
+d=9.6*10^2//kg/m^3
+awt=23
+n=2
+avg=6.023*10^26
+m=n*awt/avg
+a=(m/d)^(1/3)
+printf("The lattice constant od sodium is %.1f A°",a*10^10)
diff --git a/1826/CH2/EX2.30/ex2_30.sce b/1826/CH2/EX2.30/ex2_30.sce
new file mode 100755
index 000000000..6458048a9
--- /dev/null
+++ b/1826/CH2/EX2.30/ex2_30.sce
@@ -0,0 +1,10 @@
+// Example 2.30, page no-48
+clear
+clc
+h=3
+k=2
+l=1
+rfcc=0.1278*10^-9//m
+a=4*rfcc/sqrt(2)
+d=a/sqrt(h^2+k^2+l^2)
+printf("\nThe lattice constant = %.3f *106-10\nThe interplanar spacing for the plane(321) is %.3f*10^-11 m",a*10^10,d*10^11)
diff --git a/1826/CH2/EX2.31/ex2_31.sce b/1826/CH2/EX2.31/ex2_31.sce
new file mode 100755
index 000000000..7c99f7853
--- /dev/null
+++ b/1826/CH2/EX2.31/ex2_31.sce
@@ -0,0 +1,8 @@
+// Example 2.31, page no-49
+clear
+clc
+a=0.4049*10^-10//m
+t=0.005//m
+A=25*10^-2//m
+n=t*A/a^3
+printf("The number of atoms in the Al foil is %.2f * 10^28",n*10^-28)
diff --git a/1826/CH2/EX2.32/ex2_32.sce b/1826/CH2/EX2.32/ex2_32.sce
new file mode 100755
index 000000000..fc021f35d
--- /dev/null
+++ b/1826/CH2/EX2.32/ex2_32.sce
@@ -0,0 +1,12 @@
+// Example 2.32, page no-49
+clear
+clc
+theta=20//in degrees
+d=2*10^-10//m
+n=1
+h=6.626*10^-34
+m=1.67*10^-27//kg
+e=1.6*10^-19//C
+lam=2*d*sin(theta*%pi/180)/n
+E=(1/(2*m))*(h/lam)^(2)
+printf("\nThe deBroglie wavelength of the neutron is %.3f *10^-10\nthe energy of the neutron is %.4f eV",lam*10^10,E/e)
diff --git a/1826/CH2/EX2.35/ex2_35.sce b/1826/CH2/EX2.35/ex2_35.sce
new file mode 100755
index 000000000..3dc2c5b2d
--- /dev/null
+++ b/1826/CH2/EX2.35/ex2_35.sce
@@ -0,0 +1,13 @@
+// Example 2.35, page no-51
+clear
+clc
+e=1.6*10^-19//C
+
+h=6.626*10^-34
+m=9.1*10^-31//kg
+ek=235.2*e
+n=1
+theta=9.21
+lam=h/sqrt(2*m*ek)
+d=n*lam/(2*sin(theta*%pi/180))
+printf("\nThe deBroglie wavelength of electron is %.3f *10^-11 m\nThe interplanar spacing is %.3f *10^-10 m",lam*10^11,d*10^10)
diff --git a/1826/CH2/EX2.36/ex2_36.sce b/1826/CH2/EX2.36/ex2_36.sce
new file mode 100755
index 000000000..e67b5da86
--- /dev/null
+++ b/1826/CH2/EX2.36/ex2_36.sce
@@ -0,0 +1,11 @@
+// Example 2.36, page no-52
+clear
+clc
+// Intercepts are in the ratio 3a:4b along X,Y and parallel to Z axis
+//x intercept 3,y intercept 4 and z intercept infinity 
+a=2*10^-10// 2 Angstrom
+h=4
+k=3
+l=0
+d=a/sqrt(h^2+k^2+l^2)
+printf("The lattice spacing for the plane 430 is %.1f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.38/ex2_38.sce b/1826/CH2/EX2.38/ex2_38.sce
new file mode 100755
index 000000000..e6a3136cd
--- /dev/null
+++ b/1826/CH2/EX2.38/ex2_38.sce
@@ -0,0 +1,4 @@
+// Example 2.38, page no-53
+clear
+clc
+printf("Same as example 2.24 of the same chapter")
diff --git a/1826/CH2/EX2.4/ex2_4.sce b/1826/CH2/EX2.4/ex2_4.sce
new file mode 100755
index 000000000..a57e20c02
--- /dev/null
+++ b/1826/CH2/EX2.4/ex2_4.sce
@@ -0,0 +1,11 @@
+// Example 2.4, page no-31
+clear
+clc
+
+d=4*10^3//kg/m^3
+awtcs=132.9
+awtcl=35.5
+a=4.12*10^-10
+m=d*a^3
+N=(awtcs+awtcl)/m
+printf("The value of Avogadro Constant %.4f *10^26 per kg mole",N*10^-26)
diff --git a/1826/CH2/EX2.5/ex2_5.sce b/1826/CH2/EX2.5/ex2_5.sce
new file mode 100755
index 000000000..2245e92c2
--- /dev/null
+++ b/1826/CH2/EX2.5/ex2_5.sce
@@ -0,0 +1,10 @@
+// Example 2.5, page no-31
+clear
+clc
+lam=1.5418*10^-10//m
+theta=30//in degrees
+h=1
+k=1
+l=1
+a=lam*sqrt(h^2+k^2+l^2)/(2*sin(theta*%pi/180))
+printf("The lattice constant is %.4f *10^-10 m",a*10^10)
diff --git a/1826/CH2/EX2.6/ex2_6.sce b/1826/CH2/EX2.6/ex2_6.sce
new file mode 100755
index 000000000..352cad0f1
--- /dev/null
+++ b/1826/CH2/EX2.6/ex2_6.sce
@@ -0,0 +1,9 @@
+// Example 2.6, page no-33
+clear
+clc
+h=1
+k=0
+l=0
+a=2.814*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("The lattice spacing for the plane(100) is %.3f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.7/ex2_7.sce b/1826/CH2/EX2.7/ex2_7.sce
new file mode 100755
index 000000000..2ab942fd1
--- /dev/null
+++ b/1826/CH2/EX2.7/ex2_7.sce
@@ -0,0 +1,9 @@
+// Example 2.7, page no-33
+clear
+clc
+h=3
+k=2
+l=1
+a=4.12*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("The lattice spacing for the plane(321) is %.4f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX2.8/ex2_8.sce b/1826/CH2/EX2.8/ex2_8.sce
new file mode 100755
index 000000000..c1608243c
--- /dev/null
+++ b/1826/CH2/EX2.8/ex2_8.sce
@@ -0,0 +1,17 @@
+// Example 2.8, page no-34
+clear
+clc
+///(i)
+h=1
+k=0
+l=1
+a=4.2*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("\nThe lattice spacing for the plane(101) is %.3f*10^-10 m",d*10^10)
+///(ii)
+h=2
+k=2
+l=1
+a=4.12*10^-10
+d=a/sqrt(h^2+k^2+l^2)
+printf("\nThe lattice spacing for the plane(220) is %.1f*10^-10 m",d*10^10)
diff --git a/1826/CH2/EX20.21/ex2_21.sce b/1826/CH2/EX20.21/ex2_21.sce
new file mode 100755
index 000000000..a7796e795
--- /dev/null
+++ b/1826/CH2/EX20.21/ex2_21.sce
@@ -0,0 +1,9 @@
+// Example 2.21, page no-42
+clear
+clc
+d=8960
+m=63.54
+n=4
+avg=6.023*10^26
+a=(n*m*10^-3/(avg*d))^(1/3)
+printf("\nThe lattice constant of copper is %.4f A°",a*10^10)
-- 
cgit