MATH 101 Instructed by SIS
Post lab questions of Math 101:
1. Submit the experimental datasheet.
2. Theoretically calculate the voltage V1, V2, V and the currents I, I1, I2 using the measured values of the
resistor and the voltage sources.
3. Compare the calculated values with the measured values and comment on any observed discrepancy.
4. Determine the resistance R1, R2, R3, R4 from the measured voltages and currents using Ohm’s law. Do
these values agree with the resistance measured by the multimeter ? Comment.
5. What are the different ranges the voltmeter you used in your lab had? Which range would you use to
measure a voltage around (i)0.5V , (ii)12V ? Why? Justify your answer.
Answer to the question no. 1
Data Sheet:
1(b): For series circuit :
R1(Ω)
R2(Ω)
V1(v)
V2(v)
I(mA)
48
103
0.62
1.35
13.7
1(b): For parallel circuit :
R3(Ω)
R4(Ω)
V(v)
I1(mA)
I2(mA)
103
225
1.95
19.5
8.9
Answer to the question no. 2
For series circuit :
Vs = 2V, R1=48Ω, R2=103Ω
So,
Vs =I(R1+R2)
=>I=Vs/(R1+R2)
=>I=2/(48+103)
=>I=13.2mA
V1=I.R1
=> V1=13×48
=> V1=624mV
=> V1=0.62V
V2=I.R2
=> V1=13×103
=> V1=1339mV
=> V1=1.33V
For parallel circuit :
Vs = 1.95V, R1=103Ω, R2=225Ω
So,
V=I1×R3
=> I1=Vs/R3
=> I1=1.95/103
=> I1= 18.9 mA
V=I2×R4
=> I2=Vs/R4
=> I2=1.95/225
=> I2= 8.66 mA
Answer to the question no. 3
The comparison between calculated values and measured value is given below:
For series circuit :
Type
V1(V)
V2(V)
I(mA)
Measured
0.62
1.35
13.7
Calculated
0.62
1.33
13.3
For parallel circuit :
Type
V(V)
I1(mA)
I2(mA)
Measured
1.95
19.5
8.9
Calculated
1.95
18.9
8.66
Comment: There is a little bit difference between measured values and calculated values. I measured the voltage of resistance R2 of series circuit ,1.35V . But theoretically the value is 1.33V.on the other hand ,The current of series circuit is theoretically 13.3mA but in practical, it is 13.7mA
There is also a little bit difference between measured values and calculated values in parallel circuit. I measured the current through resistance R3 of parallel circuit ,19.5 mA. But theoretically the value is 18.9mA.on the other hand ,The current of Through R4 is theoretically 8.66mA but in practical, it is 8.9mA
Answer to the question no. 4
For R1:
V1=0.62V
I=13.7mA
From ohm’s law:
R1=V1/I
=> R1=0.62/13.7
=> R1= 45Ω
For R2:
V2=1.35V
I=13.7mA
From ohm’s law:
R2=V2/I
=> R2=1.35/13.7
=> R2= 98Ω
For R3:
V=1.95V
I1=19.5mA
From ohm’s law:
R3=V/I1
=> R3=1.95/19.5
=> R3= 100Ω
For R4:
V=1.95V
I2=8.9mA
From ohm’s law:
R4=V/I2
=> R4=1.95/8.9
=> R4= 219Ω
The comparison between calculated values and measured values of R1, R2, R3, R4 is given below :
Type(Ω)
R1(Ω)
R2(Ω)
R3(Ω)
R4(Ω)
Measured
48
103
103
225
Calculated
45
98
100
219
Comment: The calculated values does not agree with the resistance measured by multi-meter .The values ,which are measured are quiet different from the calculated values.
Answer to the question no. 5
In the lab I used different ranges in voltmeter to calculate different voltages.
To measure the voltage V1=0.62V, I used the range 1.0 v
To measure the voltage V2=1.35V, I used the range 3.0 v
To measure the voltage V=1.95V, I used the range 3.0 v
(i)to measure a voltage around 0.5 v , I will use the range 1V, because I will get the most approximate reading at the range 1.0 otherwise, it is very difficult to identify the correct value.
(ii)to measure a voltage around 12v , I will use the range 30V, because I will get the most approximate reading at the range 30 otherwise, it is very difficult to identify the correct value.
Discussion:
This experiment was the most basic experiment of EEE. After doing this experiment, it is quiet easy for us to take measurement of resistance, flow of current, voltage etc. And in this experiment, we have to joint all equipment very carefully and have to connect volt meters, ammeters, multi-meters very carefully. Otherwise, the equipment could have been damaged. We have to check and double check all connections and set the voltage very carefully. Otherwise, the there can be accidents.
1. Submit the experimental datasheet.
2. Theoretically calculate the voltage V1, V2, V and the currents I, I1, I2 using the measured values of the
resistor and the voltage sources.
3. Compare the calculated values with the measured values and comment on any observed discrepancy.
4. Determine the resistance R1, R2, R3, R4 from the measured voltages and currents using Ohm’s law. Do
these values agree with the resistance measured by the multimeter ? Comment.
5. What are the different ranges the voltmeter you used in your lab had? Which range would you use to
measure a voltage around (i)0.5V , (ii)12V ? Why? Justify your answer.
Answer to the question no. 1
Data Sheet:
1(b): For series circuit :
R1(Ω)
R2(Ω)
V1(v)
V2(v)
I(mA)
48
103
0.62
1.35
13.7
1(b): For parallel circuit :
R3(Ω)
R4(Ω)
V(v)
I1(mA)
I2(mA)
103
225
1.95
19.5
8.9
Answer to the question no. 2
For series circuit :
Vs = 2V, R1=48Ω, R2=103Ω
So,
Vs =I(R1+R2)
=>I=Vs/(R1+R2)
=>I=2/(48+103)
=>I=13.2mA
V1=I.R1
=> V1=13×48
=> V1=624mV
=> V1=0.62V
V2=I.R2
=> V1=13×103
=> V1=1339mV
=> V1=1.33V
For parallel circuit :
Vs = 1.95V, R1=103Ω, R2=225Ω
So,
V=I1×R3
=> I1=Vs/R3
=> I1=1.95/103
=> I1= 18.9 mA
V=I2×R4
=> I2=Vs/R4
=> I2=1.95/225
=> I2= 8.66 mA
Answer to the question no. 3
The comparison between calculated values and measured value is given below:
For series circuit :
Type
V1(V)
V2(V)
I(mA)
Measured
0.62
1.35
13.7
Calculated
0.62
1.33
13.3
For parallel circuit :
Type
V(V)
I1(mA)
I2(mA)
Measured
1.95
19.5
8.9
Calculated
1.95
18.9
8.66
Comment: There is a little bit difference between measured values and calculated values. I measured the voltage of resistance R2 of series circuit ,1.35V . But theoretically the value is 1.33V.on the other hand ,The current of series circuit is theoretically 13.3mA but in practical, it is 13.7mA
There is also a little bit difference between measured values and calculated values in parallel circuit. I measured the current through resistance R3 of parallel circuit ,19.5 mA. But theoretically the value is 18.9mA.on the other hand ,The current of Through R4 is theoretically 8.66mA but in practical, it is 8.9mA
Answer to the question no. 4
For R1:
V1=0.62V
I=13.7mA
From ohm’s law:
R1=V1/I
=> R1=0.62/13.7
=> R1= 45Ω
For R2:
V2=1.35V
I=13.7mA
From ohm’s law:
R2=V2/I
=> R2=1.35/13.7
=> R2= 98Ω
For R3:
V=1.95V
I1=19.5mA
From ohm’s law:
R3=V/I1
=> R3=1.95/19.5
=> R3= 100Ω
For R4:
V=1.95V
I2=8.9mA
From ohm’s law:
R4=V/I2
=> R4=1.95/8.9
=> R4= 219Ω
The comparison between calculated values and measured values of R1, R2, R3, R4 is given below :
Type(Ω)
R1(Ω)
R2(Ω)
R3(Ω)
R4(Ω)
Measured
48
103
103
225
Calculated
45
98
100
219
Comment: The calculated values does not agree with the resistance measured by multi-meter .The values ,which are measured are quiet different from the calculated values.
Answer to the question no. 5
In the lab I used different ranges in voltmeter to calculate different voltages.
To measure the voltage V1=0.62V, I used the range 1.0 v
To measure the voltage V2=1.35V, I used the range 3.0 v
To measure the voltage V=1.95V, I used the range 3.0 v
(i)to measure a voltage around 0.5 v , I will use the range 1V, because I will get the most approximate reading at the range 1.0 otherwise, it is very difficult to identify the correct value.
(ii)to measure a voltage around 12v , I will use the range 30V, because I will get the most approximate reading at the range 30 otherwise, it is very difficult to identify the correct value.
Discussion:
This experiment was the most basic experiment of EEE. After doing this experiment, it is quiet easy for us to take measurement of resistance, flow of current, voltage etc. And in this experiment, we have to joint all equipment very carefully and have to connect volt meters, ammeters, multi-meters very carefully. Otherwise, the equipment could have been damaged. We have to check and double check all connections and set the voltage very carefully. Otherwise, the there can be accidents.