#Variable declaration
n=10**6 #no. of electrons
e=1.6*10**-19 #charge on an electron in C
#Calculation
q=n*e #calculating total charge
t=10**-3 #time in second
I=q/t #calculating current
#Result
print"Current flowing = ",I,"Ampere"
#Variable declaration
I=300*10**-3 #current n Ampere
t=60 #time in second
e=1.6*10**-19 #chatge on electron in C
#Calculation
q=I*t #calculating charge
n=q/e #calculating no of electrons
#Result
print"No. of electrons = ",n
#Variable declaration
V=200 #voltage in volt
R=100 #resistance in Ohm
e=1.6*10**-19 #charge on an electron in C
#Calculation
I=V/R #Ohm's law
t=1 #time in second
q=I*t #calculating charge
n=q/e #calculating no of electrons
#Result
print"No. of electrons = ",n
#Variable declaration
l=15 #length in m
A=6*10**-7 #area in m square
R=5 #resistance in Ohm
#Calculation
p=(A*R)/l #calculating resistivity
#Result
print"Resistivity= ",p,"Ohm metre"
#Variable declaration
l=0.1 #length in m
A=10**-4 #area in m square
R=0.01 #resistance in Ohm
#Calculation
p=(A*R)/l #calculating resistivity
#Result
print"Resistivity = ",p,"Ohm metre"
import math
#Variable declaration
L=1 #length in m
r=0.2*10**-3 #radius in m
R=2 #resistance in Ohm
#Calculation
A=math.pi*(r)**2 #calculating area
P=(R*A)/L #calculating resistivity
#Result
print"Resistivity =%.2g"%P,"Ohm.metre"
#Variable declaration
R1=5 #resisitance in Ohm
#Calculation
#A2=A/3
#R2/5=3l*3/A*A/l
#R2=9*5
R2=9*R1 #calculating using R2/A1=(l2/A2)*(A1/l1)
print"Resisitance = ",R2,"Ohm"
#Variable declaration
R1=5 #resisitance in Ohm
#Calculation
#A2=A/2
#R1=rho*l1/A1*R2
#R2=rho*l2/A2
#R2/R1=A1/l1
R2=4*R1 #calculating using R2/A1=(l2/A2)*(A1/l1)
#Result
print"Resisitance= ",R2,"Ohm"
#Variable declaration
R1=2 #resisitance in Ohm
R2=4 #resistance in Ohm
R3=5 #resistance in Ohm
#Calculation
R=(R1**-1)+(R2**-1)+(R3**-1) #calculating parallel resistance
Rp=(1/R)
#Result
print"Resisitance = ",Rp,"Ohm"
print"\nNOTE:Incorrect answer in book"
from scipy.optimize import fsolve
#Variable declaration
Rs=40 #resisitance in Ohm
#Calculation
#R1+R2=40
#R1*R2=256
#R1=256/R2
#Putting this value in eq 1:
#(256/R2)+R2=40
from sympy import solve, symbols, pprint
R2= symbols('R2')
a=1
b=-40
c=256
f = a*R2**2 + b*R2 + c
solution = solve(f, R2)
#Result
print"When R2=",solution[0],"Ohm R1=",solution[1],"Ohm"
print"When R2=",solution[1],"Ohm R1=",solution[0],"Ohm"
#Variable declaration
V=2.0 #in volts
R1=30.0 #resisitance in Ohm
R2=60.0 #resistance in Ohm
#Calculation
Rp=(R1*R2)/(R1+R2) #calculating parallel resistance
I=V/Rp #Ohm's law
#Result
print"Resisitance = ",Rp,"Ohm"
print"Current = ",I,"A"
#Variable declaration
R1=2.0 #resisitance in Ohm
R2=3.0 #resistance in Ohm
R3=1.0 #resistance in Ohm
#Calculation
Rp=(R1*R2)/(R1+R2) #calculating parallel resistance
R=Rp+1.0 #1 Ohm in series
Rs=(R1+R2+R3) #series resistances
Rp=(1.0/R1)+(1.0/R2)+(1.0/R3) #calculating parallel resistance
#Result
print"(1)Equivalent Resisitance= ",R,"Ohm"
print"(2)All resistances in series = ",Rs,"Ohm"
print"(3)All in Parallel = ",(1/Rp),"Ohm"
#Variable declaration
V=20 #voltage in Volts
R1=2.0 #resisitance in Ohm
R2=4.0 #resistance in Ohm
R3=5.0 #resistance in Ohm
#Calculation
Rp=(1/R1)+(1/R2)+(1/R3) #calculating parallel resistance
R=1/Rp #Parallel
I1=V/R1 #calculating current through R1
I2=V/R2 #calculating current through R2
I3=V/R3 #calculating current through R3
I=V/R #calculating total current
#Result
print"(a)Equivalent Resisitance = ",R,"Ohm"
print"Current through R1 = ",I1,"Ampere"
print"Current through R2 = ",I2,"Ampere"
print"Total current = ",I,"Ampere"
#Variable declaration
R=7 #Total resistanc of combination
#Calculation
def f(n):
Rp = 6*(1/n) #resistance in parallel
return(R-Rp-5)
n=fsolve(f,1)
#Result
print"n=",n[0]
#Variable declaration
R1=2 #resistance in Ohm
R2=6 #resistance in Ohm
R3=3 #resistance in Ohm
V=24 #voltage in volts
R=8 #resistance in Ohm
#Calculation
I=V/R #Ohm's Law
V1=I*R1 #Ohm's Law
V2=I*R2 #Ohm's Law
V3=I*R3 #Ohm's Law
#Result
print"Current = ",I,"Ampere"
print"Voltage drop across R1 = ",V1,"Volts"
print"Voltage drop across R2 = ",V2,"Volts"
print"Voltage drop across R3 = ",V3,"Volts"
print"\nNOTE:Wrong answer of R3 in book"
#Variable declaration
R=15 #resistance in Ohm
print"KVL: 16I1+15I2=6 (1)" #KVL equation
I1=-1.66 #from(1)
I2=2.17 #from (1)
#Calculation
V=(I1+I2)*R #calculating potential difference
#Result
print"Potential difference= ",V,"Volt"
print"3I1-I2-1=0 (1)" #KVL equation
print"3I1-I2+2I=2 (2)" #KVL equation
print"3I1-I1+2I=2 (3)" #KVL equation
#Variable declaration
I1=4/17.0 #from (1)(2)(3)through AB
I2=-2/17.0 #from (1)(2)(3)through BD
I=3*I1+I2 #from (1)(2)(3)through main circuit
#Calculation
Ibc=I1-I2 #calculating current in BC
Iad=I-I1 #calculating current in AD
Idc=I-I1+I2 #calculating current in DC
#Result
print"Current in branch BC = ",Ibc,"Ampere"
print"NOTE:Calculation mistake in book while calculating for BC"
print"Current in branch AD = ",Iad,"Ampere"
print"Current in branch DC = ",Idc,"Ampere"
#Variable declaration
P=10 #Ohm
Q=3 #Ohm
R=12 #Ohm
S=6 #Ohm
G=20 #Ohm
#Calculation
print"-12I+22I1+IgG=0 (1)" #KVL
print"6I-9I1+29Ig=0 (2)" #KVL
print"13I1-3Ig=2 (3)" #KVL
#From above equations
import numpy as np
a = np.array([[-12,22,20],[6,-9,29],[0,13,-3]])
b = np.array([[0],[0],[2]])
np.linalg.solve(a,b)
#Result
print"Current through Galvanometer = ",round(Ig*1000,2),"mA"
#Variable declaration
P=500 #power in Watts
V=200 #voltage in Volts
V1=160 #voltage in Volts
#Calculation
R=(V**2)/P #using P=V**2*R
P1=(V1**2)/R #calculating power
Dp=500-P1 #drop in heat
D=(Dp*100)/500 #percentage drop
#Result
print"Resistance= ",R,"Ohm"
print"% Drop in heat production = ",D,"%"
#Variable declaration
P1=100 #power in Watts
P2=500 #power in Watts
#Calculation
P=P2/P1 #ratio
#Result
print "P=",P
print"P>0,I2=5I Therefore I2>I1"
#Variable declaration
t=1200 #time in second
P=100 #power in Watts
V=230 #voltage in Volts
#Calculation
R=(V**2)/P #calculating resistance
V1=115 #supply voltage in Volts
E=((V1**2)*t)/R #calculating energy
#Result
print"Energy dissipated by bulb = ",E,"J"
#Variable declaration
P=10**4 #power in Watts
V=250 #voltage in Volts
R=0.2 #resistance in ohm
#Calculation
Pl=((P/V)*(P/V))*R #calculating power loss
print P1
E=P/(Pl+P) #calculating efficiency
#Result
print"Percent Efficiency = ",round(E*100),"%"
#Variable declaration
P=100.0 #power in Watts
V=220.0 #voltage in Volts
#Calculation
I=P/V #Current in Ampere
R=V/I #resistance
#Result
print"Current = ",round(I,3),"A"
print"Resistance=",R,"Ohm"
#Variable declaration
V=50 #voltage in Volts
I=12 #Current in Ampere
#Calculation
P=V*I #power
Pd=P*0.7 #power dissipated
R=(Pd/(I)**2)
#Result
print"Resistance = ",round(R,2),"Ohm"