Chapter5 - Potentiometer

Exa 5.1 page 139

In [3]:
from __future__ import division
Ipq=4/(3+4) 
Vpq=Ipq*3 
Vpq_per_cm=Vpq/100 
Dpx=1.0186/Vpq_per_cm 
print "Distance PX = %.2f cm"%(Dpx)

Distance PX = 59.42 cm

Exa 5.2 page 139

In [4]:
V_per_cm=1.0186/60 
#When S is replaced by a dry cell we get PK=85 cm for null deflection
Dpk=85 
V_dry_cell=Dpk*V_per_cm 
print "Voltage of dry cell=%.2f V"%(V_dry_cell)

Voltage of dry cell=1.44 V

Exa 5.3 page 140

In [5]:
Vpq=(1.02*5/2500)*1000 
Lpq=1.2*100/Vpq 
print "Length of PQ=%.2f m"%(Lpq)

Length of PQ=58.82 m

Exa 5.4 page 140

In [6]:
l2=(10/3)*(1.5/1.5)*(9/15)**2 
print "Length of wire=%.2f m"%(l2)
a1=0.0004 
a2=0.0003 
R2=1 
R1=1.5*R2 
T=100 
Rp=R1*(1+a1*T) 
Rq=R2*(1+a2*T) 
R=Rp/Rq 
print "Ratio of resistances=%.2f"%(R)

Length of wire=1.20 m
Ratio of resistances=1.51

Exa 5.5 page 141

In [7]:
emf_std_cell=1.0183 
emf_cell=70/50*emf_std_cell 
print "e.m.f. of the cell=%.2f V"%(emf_cell)
V_read=1.35 
V_cal=1.32379 
error_voltmeter_percent=((V_read-V_cal)/V_cal)*100 
print "Perentage error of the voltmeter = %.2f"%(error_voltmeter_percent)

e.m.f. of the cell=1.43 V
Perentage error of the voltmeter = 1.98