initial commit / add all books

32 files changed, 545 insertions, 0 deletions

diff --git a/3835/CH4/EX4.1/Ex4_1.sce b/3835/CH4/EX4.1/Ex4_1.sce
new file mode 100644
index 000000000..88ea9a08f
--- /dev/null
+++ b/3835/CH4/EX4.1/Ex4_1.sce
@@ -0,0 +1,22 @@
+clear
+//
+//given
+b=0.2
+a=0.04
+n=1000/(60) //rev/sec
+t=500
+//case a
+//since coil is at right angles ang=0
+printf("\n e(t)=0 V")
+//case b
+//when coil is 30deg to the field ang=60
+//p=sin(60) 
+p=0.8660254
+e=2*3.14*a*n*b*t*p
+printf("\n e(t)= %0.1f  V",e)
+//case c
+//when ang=90 that is coil is in the plane of the field
+//p=sin(90)
+p=1
+e=2*3.14*b*a*n*p*t
+printf("\n e(t)= %0.1f  V",e)
diff --git a/3835/CH4/EX4.11/Ex4_11.sce b/3835/CH4/EX4.11/Ex4_11.sce
new file mode 100644
index 000000000..4bd67c4c5
--- /dev/null
+++ b/3835/CH4/EX4.11/Ex4_11.sce
@@ -0,0 +1,9 @@
+clear
+//
+//i1=20*sin(314t+60),i2=-10*sin(314t),i3=15*sin(314t-45)-->angles are in degrees
+//I1=(7.7072+j12.25),I2=(-7.072),I3=7.5-j7.5
+//adding phasor currents I1,I2 and I3
+//I=7.702+j12.25-7.702+7.5-j7.5=7.5+j4.75
+printf("\n I=7.5+j4.75. Its value in polar form is obtained as 8.8776 at angle 32.34")
+//i=2**0.5*8.8776*sin(314t+32.34)-->instantaneous value of resultant i
+printf("\n instantaneous value of resultant i is 12.5548*sin(314t+32.34)")
diff --git a/3835/CH4/EX4.12/Ex4_12.sce b/3835/CH4/EX4.12/Ex4_12.sce
new file mode 100644
index 000000000..846aca9b7
--- /dev/null
+++ b/3835/CH4/EX4.12/Ex4_12.sce
@@ -0,0 +1,16 @@
+clear
+//
+v=230
+f=50
+L=50*10**-3
+r=10
+//case a
+xl=2*3.14*f*L
+z=complex(r,xl)
+//the value of z in polar form is 18.62 ohm
+z=18.62
+i=v/(z)
+printf("\n i= %0.1f  A",i)
+//case b
+//phy=taninverse(xl/r)=57.52 lag
+printf("\n phase angle of current=57.52 lag")
diff --git a/3835/CH4/EX4.13/Ex4_13.sce b/3835/CH4/EX4.13/Ex4_13.sce
new file mode 100644
index 000000000..46738a49c
--- /dev/null
+++ b/3835/CH4/EX4.13/Ex4_13.sce
@@ -0,0 +1,11 @@
+clear
+//
+vr=150
+r=50
+l=250*10**-3
+f=50
+i=vr/r
+xl=2*3.14*f*l
+vl=i*xl
+v=(((vr**2)+(vl**2))**0.5)
+printf("\n v= %0.1f  V",v)
diff --git a/3835/CH4/EX4.14/Ex4_14.sce b/3835/CH4/EX4.14/Ex4_14.sce
new file mode 100644
index 000000000..80a913cfe
--- /dev/null
+++ b/3835/CH4/EX4.14/Ex4_14.sce
@@ -0,0 +1,22 @@
+clear
+//
+v=200
+f=50
+r=20
+vr=100
+vc=144
+vl=150
+//case a
+//from eqn ((vr**2+vl*cos1(angle))**2)+((vl*sin(angle))**2)=v**2
+//on substituting values in the above eqn the value of angle can be found by isolating cos1
+//angle=75.52
+cos1=0.25
+pf=(vr+vl*cos1)/(v)
+printf("\n pf")
+//case b
+i=vr/r
+power=i**2*r
+printf("\n power consumed= %0.1f  w",power)
+//case c
+power=vl*i*cos1
+printf("\n power consumed in choke oil= %0.1f  W",power)
diff --git a/3835/CH4/EX4.15/Ex4_15.sce b/3835/CH4/EX4.15/Ex4_15.sce
new file mode 100644
index 000000000..a3d7ba78d
--- /dev/null
+++ b/3835/CH4/EX4.15/Ex4_15.sce
@@ -0,0 +1,25 @@
+clear
+//
+r=10
+c=10**-4
+v=230
+f=50
+omega=314
+//case a
+xc=1/(omega*c)
+printf("\n xc= %0.1f  ohm",xc)
+//case b
+zc=33.38 //zc=10-j31.85 into polar form is 33.38
+i=v/zc
+printf("\n i= %0.1f  A",i)
+//case c
+pf=r/zc
+printf("\n pf")
+//case d
+//phase angle=cosinverse(0.3)=72.6
+printf("\n phase angle=72.6")
+//case e
+v=r*i
+printf("\n v= %0.1f  v",v)
+v=xc*i
+printf("\n v= %0.1f  v",v)
diff --git a/3835/CH4/EX4.16/Ex4_16.sce b/3835/CH4/EX4.16/Ex4_16.sce
new file mode 100644
index 000000000..de94ea6a1
--- /dev/null
+++ b/3835/CH4/EX4.16/Ex4_16.sce
@@ -0,0 +1,19 @@
+clear
+//
+v=230
+f=50
+//voltage vr across r is in phase with the current i while voltage vc across c lage i by 90
+//from phasor diagram v**2=vr**2+vc**2
+vr=100
+vc=((v**2)-(vr**2))**0.5
+printf("\n vc= %0.1f  v",vc)
+p=500 //power
+i=p/vr
+c=i/(2*3.14*f*vc)
+printf("\n c= %e  F",c)
+//case b
+v=(2**0.5)*vc
+printf("\n maximum voltage across c= %0.1f  V",v)
+//case c
+//phase angle=cosinverse(vr/v)=cosinverse(0.4348)=64.2
+printf("\n phase angle=64.2")
diff --git a/3835/CH4/EX4.17/Ex4_17.sce b/3835/CH4/EX4.17/Ex4_17.sce
new file mode 100644
index 000000000..52ea84c1a
--- /dev/null
+++ b/3835/CH4/EX4.17/Ex4_17.sce
@@ -0,0 +1,30 @@
+clear
+//
+r=8
+l=0.15
+f=50
+v=230
+c=125*10**-6
+//case a inductive reactance
+xl=2*3.14*f*l
+printf("\n xl= %0.1f  ohm",xl)
+//case b capacitance reactance
+xc=1/(2*3.14*f*c)
+printf("\n xc= %0.0f ohm",xc)
+//case c complex impedance
+//z=r+j(xl-xc)-->on substituting valuees we get z=8+j21.62
+//z=((8**2)+(21.62**2))**0.5
+printf("\n complex impedance=8+j21.62 at an impedance angle of 69.7")
+//impedance angle=taninverse(xl-xr)/r
+//case d
+v=230
+z=23.05
+i=v/z
+printf("\n current= %0.1f  A",i)
+//case e
+//(r+jxl)*i=446.8 at 10.66 degrees
+printf("\n voltage across coil=446.8 at 10.66 degrees")
+//-j*xc*i=25.48*9.98
+printf("\n voltage across capacitor=-254.29 at -159.7 degrees")
+//case e
+printf("\n phase difference between supply and current i is 69.7 lag')
diff --git a/3835/CH4/EX4.18/Ex4_18.sce b/3835/CH4/EX4.18/Ex4_18.sce
new file mode 100644
index 000000000..125f4ace1
--- /dev/null
+++ b/3835/CH4/EX4.18/Ex4_18.sce
@@ -0,0 +1,28 @@
+clear
+//
+c=50*10**-6
+i=2.355
+//case a
+vl=120
+vr=70
+vac=150
+//the phasor sum of vr and vl is OCthe applied voltage v is the phasor sum of vc and OC and is represented by OV
+//the theta be the impedance angle of RL combination
+//from right angled triangle OCD,theta can be determined as follows:
+//(vr+vl*costheta)**2+(vl*costheta)**2=vac**2
+//substitute the values then value of costheta can be found
+zl=vl/i //impedance of the coil
+p=0.981 //value of sin(79)
+xl=zl*p
+q=0.19 //value of cos(79)
+r=zl*q
+dc=i*xl
+bd=i*r
+//from right angled triangle ODB in fig.
+v=98.3
+xc=vac/i
+printf("\n capacitive reactance= %0.1f  ohm",xc)
+f=1/(xc*2*3.14*c)
+printf("\n f= %0.1f  cycles/sec",f)
+ploss=i**2*r
+printf("\n power loss in iron cored choke is= %0.1f  w",ploss)
diff --git a/3835/CH4/EX4.19/Ex4_19.sce b/3835/CH4/EX4.19/Ex4_19.sce
new file mode 100644
index 000000000..736c28004
--- /dev/null
+++ b/3835/CH4/EX4.19/Ex4_19.sce
@@ -0,0 +1,11 @@
+clear
+//
+r=20
+l=200*10**-3
+v=230
+f=50
+xl=314*l //314 is omega
+ir=v/(r)
+il=v/(xl)
+i=((ir**2)+(il**2))**0.5
+printf("\n i= %0.1f  A",i)
diff --git a/3835/CH4/EX4.2/Ex4_2.sce b/3835/CH4/EX4.2/Ex4_2.sce
new file mode 100644
index 000000000..9e41ffa41
--- /dev/null
+++ b/3835/CH4/EX4.2/Ex4_2.sce
@@ -0,0 +1,18 @@
+clear
+//
+//given
+vm=155
+omega=377
+//case a
+t=(2*3.14)/(omega)
+printf("\n t= %e  sec",t)
+//case b
+f=1/(t)
+printf("\n f= %e  Hz",f)
+//case c
+v=109.60 //rms value
+//at t=0 -77.5=155*sin(ang)
+//therefore, ang=-0.5236 rad
+ang=-0.5236
+t=ang/omega
+printf("\n t= %e  sec",t)
diff --git a/3835/CH4/EX4.20/Ex4_20.sce b/3835/CH4/EX4.20/Ex4_20.sce
new file mode 100644
index 000000000..206174e7b
--- /dev/null
+++ b/3835/CH4/EX4.20/Ex4_20.sce
@@ -0,0 +1,12 @@
+clear
+//
+r=100
+c=50*10**-6
+f=50
+v=230
+//case a
+xc=-1/(314*c) //314 is omega
+ir=v/r //with angle 0
+ic=230/(xc) //with angle of 90 deg
+i=((ir**2)+(ic**2))**0.5
+printf("\n current with a lead of 57.5 is obtained as= %0.1f  A",i)
diff --git a/3835/CH4/EX4.21/Ex4_21.sce b/3835/CH4/EX4.21/Ex4_21.sce
new file mode 100644
index 000000000..c4eddcd28
--- /dev/null
+++ b/3835/CH4/EX4.21/Ex4_21.sce
@@ -0,0 +1,16 @@
+clear
+//
+r=100
+l=0.1
+c=150*10**-6
+v=230
+f=50
+//case a
+xl=314*l //at 90 deg
+xc=1/(314*c) //at lag -90 deg
+ir=v/r //at 0 deg
+il=v/xl
+ic=v/xc
+//i=ir+ic+il-->2.3+j3.51
+i=((2.3**2)+(3.51**2))**0.5
+printf("\n current at 56.76 lead= %0.1f  A",i)
diff --git a/3835/CH4/EX4.22/Ex4_22.sce b/3835/CH4/EX4.22/Ex4_22.sce
new file mode 100644
index 000000000..3de2e7f49
--- /dev/null
+++ b/3835/CH4/EX4.22/Ex4_22.sce
@@ -0,0 +1,10 @@
+clear
+//
+z1=18.03 //z1=10+j15 converted to polar form also it is at angle 56.31
+z2=32.02
+z3=10.77
+//ybc=1/zbc=(1/z2+1/z3)=1/32.02+1/10.77
+//on performing the add operation we get the value of zbc as 8.159-j9.553 that is in rectangular form
+printf("\n The value of zbc is 8.159-j9.553")
+//thus total impedance between terminals A and C is given by zac=z1+zbc
+printf("\n zac=18.159+j5.447(in rectangular form)")
diff --git a/3835/CH4/EX4.23/Ex4_23.sce b/3835/CH4/EX4.23/Ex4_23.sce
new file mode 100644
index 000000000..498678065
--- /dev/null
+++ b/3835/CH4/EX4.23/Ex4_23.sce
@@ -0,0 +1,34 @@
+clear
+//
+r1=25
+l1=0.159
+r2=60
+c=125*10**-6
+v=230
+f=50
+//case a
+xl=2*3.14*f*l1
+z1=((r1**2)+(xl**2))**0.5
+i1=v/z1
+//phy1=cosinverse(r1/z1)=63.43 lag
+xc=1/(2*3.14**c)
+z2=((r2**2)+(xc**2))**0.5
+i2=v/z2
+//i2 has 23 deg lead calculated similar to i1
+//p=cosphy1
+//q=cosphy2
+p=0.44
+q=0.92
+I1=i1*p+i2*q
+a=-0.89
+b=0.39
+I2=i1*a+i2*b
+I=((I1**2)+(I2**2))**0.5
+printf("\n I= %0.1f  A",I)
+//case b
+z=v/I
+printf("\n z= %0.1f  ohm",z)
+R=(z*I1)/I //note the value of I in text is printed wrongly so the result may vary
+printf("\n R= %0.1f  ohm",R)
+x=(z*I2)/I //same note applicable here as well
+printf("\n x= %0.1f  ohm",x)
diff --git a/3835/CH4/EX4.24/Ex4_24.sce b/3835/CH4/EX4.24/Ex4_24.sce
new file mode 100644
index 000000000..75365dcf3
--- /dev/null
+++ b/3835/CH4/EX4.24/Ex4_24.sce
@@ -0,0 +1,21 @@
+clear
+//
+//given
+//z1=15+j20
+//z2=8-j10
+I=20
+z1=25 //in polar form at angle 53.13
+z2=12.81 //at angle -51.34
+//v=I1z1=I2z2
+//I2=1.95I1
+//from diagram I**2=(I1cosang1+I2cosang2)**2+(I2sinang2-I1sinang1)**2
+//on substituting values in the above eqn and simplifying
+I1=6.78
+printf("\n I1=6.78A")
+I2=13.22
+//substitute this in I2=1.95I1
+printf("\n I2=13.22A")
+pow1=I1**2*15
+pow2=I2**2*8
+printf("\n power loss in z1= %0.1f  W",pow1)
+printf("\n power loss in z2= %0.1f  W",pow2)
diff --git a/3835/CH4/EX4.26/Ex4_26.sce b/3835/CH4/EX4.26/Ex4_26.sce
new file mode 100644
index 000000000..c0f3b0061
--- /dev/null
+++ b/3835/CH4/EX4.26/Ex4_26.sce
@@ -0,0 +1,9 @@
+clear
+//
+z1=complex(6,-10)
+z2=complex(10,15)
+z3=complex(18,12)
+//z1+z2 is parallel to z3
+zab=z1+(z2*z3)/(z2+z3)
+printf("\n zab")
+printf("\n the phase angle is -12.11")
diff --git a/3835/CH4/EX4.29/Ex4_29.sce b/3835/CH4/EX4.29/Ex4_29.sce
new file mode 100644
index 000000000..9ad1928ef
--- /dev/null
+++ b/3835/CH4/EX4.29/Ex4_29.sce
@@ -0,0 +1,17 @@
+clear
+//
+//case a
+l=0.25
+f=50
+v=230
+r=2
+c=1/(((2*3.14*f)**2)*l)
+printf("\n c= %e  ",c)
+//case b
+i=v/r
+printf("\n i= %0.1f  A",i)
+//case c
+vl=2*3.14*f*l*i
+vc=i/(c*2*3.14*f)
+q=(2*3.14*f*l)/(r)
+printf("\n q")
diff --git a/3835/CH4/EX4.3/Ex4_3.sce b/3835/CH4/EX4.3/Ex4_3.sce
new file mode 100644
index 000000000..a44645e7d
--- /dev/null
+++ b/3835/CH4/EX4.3/Ex4_3.sce
@@ -0,0 +1,19 @@
+clear
+//
+//given
+//i=14.14*sin(314t)-->i=im*sin(omega*t)
+//case a
+im=14.14
+i=14.14/1.414 //1.414 is  the value of root 2
+printf("\n i= %0.1f  A",i)
+//case b
+//omega=314=2*3.14*f
+f=314/(2*3.14)
+printf("\n f= %0.1f  A",f)
+//case c
+t=0.002
+//i=im*sin(omega*t)
+p=0.01096 //value of sin(omega*t)
+i=im*p
+printf("\n i= %0.1f  A",i)
+printf("\n NOTE:Answer calculated wrongly in textbook for i obtained here")
diff --git a/3835/CH4/EX4.30/Ex4_30.sce b/3835/CH4/EX4.30/Ex4_30.sce
new file mode 100644
index 000000000..f572f91b9
--- /dev/null
+++ b/3835/CH4/EX4.30/Ex4_30.sce
@@ -0,0 +1,19 @@
+clear
+//
+l=10
+r=100
+i=1
+f=100
+i1=0.5
+c=1/(4*(3.14**2)*(r**2)*l)
+v=i*r
+z=v/i1
+//z=100+jX
+x=((200**2)-(100**2))**0.5
+omega=641.1 //angular frequency in rad/sec
+f0=omega/(2*3.14)
+f1=f0-(r/(4*3.14*l))
+f2=f0+(r/(4*3.14*l))
+printf("\n f0= %0.1f  Hz",f0)
+printf("\n f1= %0.1f  Hz",f1)
+printf("\n f2= %0.1f  Hz",f2)
diff --git a/3835/CH4/EX4.31/Ex4_31.sce b/3835/CH4/EX4.31/Ex4_31.sce
new file mode 100644
index 000000000..1c125702c
--- /dev/null
+++ b/3835/CH4/EX4.31/Ex4_31.sce
@@ -0,0 +1,8 @@
+clear
+//
+v=3*10**8
+lamb=3000
+c=0.0005*10**-6
+f=v/lamb
+l=1/(4*3.14*3.14*f**2*c)
+printf("\n l= %e  H",l)
diff --git a/3835/CH4/EX4.32/Ex4_32.sce b/3835/CH4/EX4.32/Ex4_32.sce
new file mode 100644
index 000000000..f53d9b5c1
--- /dev/null
+++ b/3835/CH4/EX4.32/Ex4_32.sce
@@ -0,0 +1,17 @@
+clear
+//
+r=1500
+l=0.2
+v=1.5
+f=15000
+//case a
+//p=1/0.2c
+p=(4*3.14*3.14*f**2)+(r**2)/(l**2)
+c=1/(0.2*p)
+printf("\n c= %e  F",c)
+//case b
+z=l/(c*r)
+printf("\n z= %0.1f  ohm",z)
+//case c
+i=v/(z)
+printf("\n i= %0.1f  A",i)
diff --git a/3835/CH4/EX4.33/Ex4_33.sce b/3835/CH4/EX4.33/Ex4_33.sce
new file mode 100644
index 000000000..a0d8da52e
--- /dev/null
+++ b/3835/CH4/EX4.33/Ex4_33.sce
@@ -0,0 +1,12 @@
+clear
+//
+//the eqns are formed using the given diagram
+//the derivations from the eqns are obtained as below using matrices for their construction
+//the below eqns are in polar form
+delta=0.3165
+delta1=5.95
+delta2=6.82
+v1=delta1/delta
+printf("\n v1 at -47.63 is= %0.1f  V",v1)
+v2=delta2/delta
+printf("\n v2 at -42.30 is= %0.1f  V",v2)
diff --git a/3835/CH4/EX4.34/Ex4_34.sce b/3835/CH4/EX4.34/Ex4_34.sce
new file mode 100644
index 000000000..ce97a3c5e
--- /dev/null
+++ b/3835/CH4/EX4.34/Ex4_34.sce
@@ -0,0 +1,14 @@
+clear
+//
+//in polar form
+z1=10
+z2=12.806
+z3=13.416
+//the mesh currents are written in matrix form
+delta=329.31 //in polar form
+delta1=360
+delta2=793.22
+i1=delta1/delta
+i2=delta2/delta
+i=i1-i2 //answer obtained in text is wrongly printed
+printf("\n i at -84.21 is= %0.1f  V",i)
diff --git a/3835/CH4/EX4.35/Ex4_35.sce b/3835/CH4/EX4.35/Ex4_35.sce
new file mode 100644
index 000000000..ca622f478
--- /dev/null
+++ b/3835/CH4/EX4.35/Ex4_35.sce
@@ -0,0 +1,21 @@
+clear
+//
+//superposition theorem
+r=4
+//z=4+(8+6j)*(0-j10)/8+j6+0-j10
+//z=14-j5
+z=14.87
+l=40
+//I1a=z/l=2.69 in polar form
+I1a=complex(2.533,0.904)
+I2a=complex(-0.324,-2.67)
+//from fig c
+z=complex(2.93,-9.47)
+I1b=complex(-0.895,3.935)
+I2b=complex(1.056,-2.474)
+I1=I1a+I1b
+printf("\n I1")
+I2=I2a+I2b
+printf("\n I2")
+I=I1+I2
+printf("\n I")
diff --git a/3835/CH4/EX4.36/Ex4_36.sce b/3835/CH4/EX4.36/Ex4_36.sce
new file mode 100644
index 000000000..456a2dfd0
--- /dev/null
+++ b/3835/CH4/EX4.36/Ex4_36.sce
@@ -0,0 +1,12 @@
+clear
+//
+//thevenin's theorem
+//all the values are derived from the figures
+z1=complex(8,-6)
+z2=complex(0,5)
+zth=(z1*z2)/(z1+z2)
+printf("\n zth")
+vth=complex(-17.71,141.54)
+zload=complex(4,3)
+I=vth/(zth+zload)
+printf("\n I")
diff --git a/3835/CH4/EX4.37/Ex4_37.sce b/3835/CH4/EX4.37/Ex4_37.sce
new file mode 100644
index 000000000..7e6be9bac
--- /dev/null
+++ b/3835/CH4/EX4.37/Ex4_37.sce
@@ -0,0 +1,13 @@
+clear
+//
+//norton's theorem
+//values derived and calculated from figure
+v=complex(230,0)
+xl=complex(8,-6)
+isc=v/xl
+IN=isc
+rl=complex(0,5)
+zn=(rl*xl)/(rl+xl)
+zload=complex(4,3)
+I=(IN*zn)/(zn+zload)
+printf("\n I")
diff --git a/3835/CH4/EX4.38/Ex4_38.sce b/3835/CH4/EX4.38/Ex4_38.sce
new file mode 100644
index 000000000..4f6f2821b
--- /dev/null
+++ b/3835/CH4/EX4.38/Ex4_38.sce
@@ -0,0 +1,14 @@
+clear
+//
+//all values derived from figure
+//zth=complex(0.923,2.615)
+//vth=complex(-4.615,-6.923) //derived using formula
+//zl=complex(0.923,-2.615)
+//z=zl+zth
+vth=8.32 //polar form
+z=1.846
+I=vth/z
+printf("\n I= %0.1f  A",I)
+rl=0.923
+pl=(I**2)*rl
+printf("\n pl= %0.1f  w",pl)
diff --git a/3835/CH4/EX4.4/Ex4_4.sce b/3835/CH4/EX4.4/Ex4_4.sce
new file mode 100644
index 000000000..d008291cf
--- /dev/null
+++ b/3835/CH4/EX4.4/Ex4_4.sce
@@ -0,0 +1,10 @@
+clear
+//
+i=20
+im=i/(1.414) //that is i*root 2
+//the heat produced by i is the sum of heat produced by dc and ac current
+p=i**2
+q=im**2
+r=p+q
+I=(r**0.5)
+printf("\n I= %0.1f  A",I)
diff --git a/3835/CH4/EX4.5/Ex4_5.sce b/3835/CH4/EX4.5/Ex4_5.sce
new file mode 100644
index 000000000..90ef398bf
--- /dev/null
+++ b/3835/CH4/EX4.5/Ex4_5.sce
@@ -0,0 +1,20 @@
+clear
+//
+f=50
+irms=10
+im=irms/(0.707)
+//omega*t=2*3.14*f*t here the value for t can be substituted and value for i can be found from i=im*sin(omega*t)
+t=0.0025
+p=0.0137 //value of sin(314*0.0025)
+i=(10*p)/(0.707)
+printf("\n i= %0.1f  A",i)
+//maximum value is when 314*t=%pi/2 (in radians)-->t=0.005
+//hence at t=0.005+0.0125=0.0175 the value of i nedds to be found
+p=0.0957
+i=(10*p)/(0.707)
+printf("\n i= %0.1f  A",i)
+printf("\n NOTE:The answer given in text is printed wrongly")
+i=7.07
+//7.07=(10*sin314t)/0.707-->t=0.00833 sec
+t=0.00833-0.005 //the time at which the instaneous value is 7.07A after positive maximum value is at this time
+printf("\n t= %e  A",t)
diff --git a/3835/CH4/EX4.6/Ex4_6.sce b/3835/CH4/EX4.6/Ex4_6.sce
new file mode 100644
index 000000000..6ffd7a5e5
--- /dev/null
+++ b/3835/CH4/EX4.6/Ex4_6.sce
@@ -0,0 +1,23 @@
+clear
+//
+//from graph 
+a=0
+b=5**2
+c=10**2
+c=20**2
+d=40**2
+e=50**2
+f=40**2
+g=20**2
+h=10**2
+i=5**2
+v=(0.1*(a+b+c+d+e+f+g+h+i))**0.5 //%pi and omega values get cancelled
+printf("\n v= %0.1f  V",v)
+vavg=0.1*(0+5+10+20+40+50+40+20+10+5)
+printf("\n vavg= %0.1f  v",vavg)
+ff=v/(vavg)
+printf("\n %0.1f",ff)
+pf=50/(v) //50 is the maximum value
+printf("\n %0.1f",pf)
+v=0.707*50 
+printf("\n rms value for a sin wave with the same peak value is= %0.1f  V",v)
diff --git a/3835/CH4/EX4.8/Ex4_8.sce b/3835/CH4/EX4.8/Ex4_8.sce
new file mode 100644
index 000000000..f6a489f98
--- /dev/null
+++ b/3835/CH4/EX4.8/Ex4_8.sce
@@ -0,0 +1,13 @@
+clear
+//
+//from phasor diagram vac=vab+vbc
+hcab=60
+vcab=60
+hcbc=45
+vcbc=77.94 //vbc=60*sin(60)
+p=(vcab+hcbc)**2
+q=vcbc**2
+vac=((p+q)**0.5)
+printf("\n vac= %0.1f  v",vac)
+//the angle is given by ang=taninverse(vcbc/(vcab+hcbc))=36.59
+printf("\n phase position with respect to vbc=60-36.59=23.41")