{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Chapter 1:Introduction to electrical engineering"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.1:Page number-6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "E= 90065423.52 N\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "q1=q2=0.1\n",
    "r=1\n",
    "e=8.84*(10**-12)\n",
    "\n",
    "E=(q1*q2)/float(4*3.14*e*(r**2))\n",
    "\n",
    "print \"E=\",format(E,'.2f'),\"N\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.2:Page number-7"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "5.52146091786 J\n",
      "Vab=-vba=5.4V\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#given\n",
    "\n",
    "q1=2*(10**-9)\n",
    "q2=3*(10**-9)\n",
    "\n",
    "#q1 and q2 are 6m apart in air\n",
    "#on substituting the values in the formula for calculating force between q and q1 and q and q2 we get 9[(3/(6-x**2)-(2/(x**2)))]\n",
    "\n",
    "import sympy as sp\n",
    "x=sp.Symbol('x')\n",
    "sp.integrate(((3/(6-x)**2)-(2/x**2)),x)\n",
    "\n",
    "from scipy.integrate import quad\n",
    "import scipy.integrate\n",
    "\n",
    "def f(x):\n",
    "    return -(x+12)/(x**2 - 6*x)\n",
    "    \n",
    "    \n",
    "    \n",
    "\n",
    "i=quad(f,1,4)\n",
    "print (i[0]),\"J\"\n",
    "\n",
    "\n",
    "print \"Vab=-vba=5.4V\"\n",
    "\n",
    "#the value obtained is directly given with print \n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.3:Page number-11"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "iav= 1.6 A\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "charge=1.6*(10**-19)\n",
    "iav=1.6*(10**-19)*(10**19) #total charge movement per second\n",
    "\n",
    "print \"iav=\",format(iav,'.1f'),\"A\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.4:Page number-14"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "energy of each coulomb of charge= 3.0 J\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "p=30\n",
    "i=10\n",
    "\n",
    "v=p/i\n",
    "dt=1\n",
    "dq=i*dt\n",
    "\n",
    "dw=v*dq\n",
    "energy=dw/i\n",
    "\n",
    "print \"energy of each coulomb of charge=\",format(energy,'.1f'),\"J\"\n",
    "\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.5"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "torque= 95.54 Nm\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#given\n",
    "\n",
    "p=15000\n",
    "n=1500\n",
    "\n",
    "t=(60*p)/float(1500*2*3.14)\n",
    "\n",
    "print \"torque=\",format(t,'.2f'),\"Nm\"\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "collapsed": true
   },
   "source": [
    "## Example 1.6:Page number-16"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " R= 0.1376 ohm\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "res=1.72*(10**-8)\n",
    "l=200\n",
    "a=25*(10**-6)\n",
    "\n",
    "R=(res*l)/float(a)\n",
    "\n",
    "print \"R=\",format(R,'.4f'),\"ohm\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.7 "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "R= 0.00000270 ohm\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#given and derived\n",
    "meanrad=0.08\n",
    "meanlen=3.14*meanrad\n",
    "a=0.04*0.04\n",
    "res=1.72*(10**-8)\n",
    "\n",
    "R=(res*meanlen)/float(a)\n",
    "\n",
    "print \"R=\",format(R,'.8f'),\"ohm\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.8:Page number-17 "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "R= 80.0000 ohm\n",
      "power= 661.25 W\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "res=0.02*(10**-6)\n",
    "l=4000*80*(10**-2)\n",
    "a=0.8*(10**-6)\n",
    "\n",
    "R=(res*l)/float(a)\n",
    "\n",
    "print \"R=\",format(R,'.4f'),\"ohm\"\n",
    "\n",
    "power=(230*230)/float(80)\n",
    "\n",
    "print \"power=\",format(power,'.2f'),\"W\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.9"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "R= 0.2675 ohm\n",
      "0.40127388535\n",
      "dcu= 0.000569 nm\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "lal=7.5\n",
    "lcu=6\n",
    "rcu=0.017*(10**-6)\n",
    "ral=0.028*(10**-6)\n",
    "d=(10**-6)\n",
    "a=((3.14*d))/float(4)\n",
    "Ral=(lal*ral)/float(a)\n",
    "\n",
    "print \"R=\",format(Ral,'.4f'),\"ohm\"\n",
    "\n",
    "ial=3\n",
    "\n",
    "pv=Ral*ial\n",
    "\n",
    "\n",
    "Rcu=pv/float(2)\n",
    "print Rcu\n",
    "\n",
    "a=(rcu*lcu)/float(Rcu)\n",
    "\n",
    "dcu=(((a*4)/3.14)**0.5)\n",
    "\n",
    "print \"dcu=\",format(dcu,'.6f'),\"nm\"\n",
    "\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.10"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "l= 2706.896552 cm\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#given and derived\n",
    "\n",
    "a=100/0.32 #area required to dissipate 100W power\n",
    "d=5\n",
    "#length of cyclinder L,length of wire if l,diameter of the wire is d\n",
    "L=a/float(3.14*d)\n",
    "\n",
    "r=100/1**2\n",
    "\n",
    "#spacing is d cm\n",
    "#distance along the axis of the cylinder is 2d cm\n",
    "\n",
    "#no of turns is 10/d\n",
    "#length of one turn of the wire is 3.14*5 cm\n",
    "#length of the wire is 50*3.14/d\n",
    "res=10**-4\n",
    "\n",
    "#d=(((2*10**-4))**(0.6))\n",
    "d=0.058\n",
    "\n",
    "l=(50*3.14)/d\n",
    "\n",
    "print \"l=\",format(l,'.6f'),\"cm\"\n",
    "\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.11: Page number-20"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "t= 84.62 centigrade\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#given\n",
    "v=250\n",
    "i=5\n",
    "i1=3.91\n",
    "\n",
    "t0=0.00426 #temperature coefficient\n",
    "\n",
    "r15=v/i #at 15 degrees\n",
    "\n",
    "rt=v/i1 #at t degrees\n",
    "\n",
    "l=(rt*(1+t0*15))/50 #left hand side\n",
    "\n",
    "t=(l-1)/t0\n",
    "\n",
    "print \"t=\",format(t,'.2f'),\"centigrade\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.12"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "al2=al1/(1+al1*(t1-t2))\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#this is a derivation by substitution problem\n",
    "\n",
    "#al1=al0/(1+al0*t1)\n",
    "#al2=al0/(1+al0*t2)\n",
    "#where t1 and t2 are different temperatures al0,al1 and al2 are temperature coefficients\n",
    "\n",
    "#substitute al0 in al2\n",
    "\n",
    "#on deriving and solving for al2 we get,\n",
    "print \"al2=al1/(1+al1*(t1-t2))\"\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.13:Page number-22"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "v= 20.0 v\n",
      "v= -10.0 v\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#values are obtained from the graph\n",
    "\n",
    "i=10 #10t A for 0 to 1 second\n",
    "\n",
    "d=10 #where di/dt is 10\n",
    "L=2\n",
    "# at one second\n",
    "\n",
    "v=L*d\n",
    "\n",
    "print \"v=\",format(v,'.1f'),\"v\"\n",
    "\n",
    "#for 1 to 5 seconds\n",
    "\n",
    "d=-5\n",
    "\n",
    "#at t=3 seconds voltage across the inductor is\n",
    "\n",
    "v=L*d\n",
    "print \"v=\",format(v,'.1f'),\"v\"\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.16:Page number-27"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " i= 0.0005 A\n",
      "q= 0.0005 C\n",
      "p= 0.0100 W\n",
      "wc= 0.0050 J\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#given\n",
    "\n",
    "dv=20 #dv/dt\n",
    "c=25*(10**-6)\n",
    "\n",
    "#case a\n",
    "\n",
    "i=c*dv\n",
    "\n",
    "print \"i=\",format(i,'.4f'),\"A\"\n",
    "\n",
    "#case b\n",
    "q=c*dv\n",
    "\n",
    "print \"q=\",format(q,'.4f'),\"C\"\n",
    "\n",
    "#case c\n",
    "\n",
    "p=dv*i\n",
    "\n",
    "print \"p=\",format(p,'.4f'),\"W\"\n",
    "\n",
    "#case d\n",
    "v=dv**2\n",
    "wc=(c*v)/2\n",
    "\n",
    "print \"wc=\",format(wc,'.4f'),\"J\"\n",
    "    "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "collapsed": true
   },
   "source": [
    "## Example 1.18:Page number-34"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "f= 75.0 N\n",
      "p= 375.0 W\n",
      "e= 7.5 V\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "l=1\n",
    "b=1.5\n",
    "i=50\n",
    "u=5\n",
    "\n",
    "#case a\n",
    "\n",
    "f=b*i*l\n",
    "\n",
    "print \"f=\",format(f,'.1f'),\"N\"\n",
    "\n",
    "#case b\n",
    "\n",
    "p=f*u\n",
    "\n",
    "print \"p=\",format(p,'.1f'),\"W\"\n",
    "\n",
    "#case c\n",
    "\n",
    "e=b*l*u\n",
    "\n",
    "print \"e=\",format(e,'.1f'),\"V\"\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.19:Page number-35"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "e= 30.0 V\n",
      "e= 15.0 V\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#e=b*l*u*sin(angle)\n",
    "\n",
    "b=0.5\n",
    "l=40\n",
    "u=1.5\n",
    "\n",
    "#when angle=90 sin(90)=1=s\n",
    "s=1\n",
    "e=b*l*u*s\n",
    "\n",
    "print \"e=\",format(e,'.1f'),\"V\"\n",
    "\n",
    "#when angle=30 sin(angle)=s=0.5\n",
    "s=0.5\n",
    "e=b*l*u*s\n",
    "\n",
    "print \"e=\",format(e,'.1f'),\"V\"\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 1.22:Page number-37"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "vse= 8.0 V\n"
     ]
    }
   ],
   "source": [
    "import math\n",
    "\n",
    "#applying kcl to circuit at node b i3+i4=6-4=2\n",
    "i3=i4=1 #potential of node b with respect to node c\n",
    "vb=8\n",
    "vba=2 #voltage drop across nodes b and a\n",
    "va=6 #potential of node a w.r.t note c\n",
    "i2=3\n",
    "#applying kcl to node a\n",
    "\n",
    "isa=1\n",
    "\n",
    "vs=va+2*isa\n",
    "\n",
    "print \"vse=\",format(vs,'.1f'),\"V\"\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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