Solved Examples
2
RA Rπd
πd
2
We know that, ρ
=
=
QA
=
Example 1. The potential difference between the
l
4l
4
terminals of an electric heater is 75 V when it draws
4
2
30×
π
×(6×10
)
=
a current of 5 A from the source. What current will the
4×
2
heater draw, if the potential difference is increased to
6
=
4.24
×10
Ω-m
150 V ?
The resistivity of the metal at 25°C is 4.24
×
106
Ω-m.
Sol. Given, potential difference, V = 75 V
Current,
I=5A
Example 4. Three resistors of 5 Ω, 10 Ω and 15 Ω are
V
connected in series with a 12 V power supply. Calculate
We know that, R
=
I
their combined resistance, the current that flows in the
75
R=
=15 Ω
circuit and in each resistor and the potential difference
5
across each resistor.
When potential difference is increased to150 V, then
Sol.
Given, R1
=
5
Ω, R2 = 10 Ω, R3 = 15 Ω, V = 12 V,
current is
R = ?, I= ? and V,V ,V
= ?
1
2
3
Vʹ
150
Iʹ
=
=
=10 A
R
15
10 Ω
15 Ω
So, the current through the heater becomes 10 A.
I
I
Example 2. A wire of given material having length l and
area of cross-section A has a resistance of 10 Ω. What would
be the resistance of another wire of the same material
+
-
12 V
having length l/4 and area of cross-section 2.5A?
According to question, the three resistors are connected in
Sol. For first wire, length = l, area of cross-section = A
series combination, then equivalent resistance,
and resistance, R1 =10 Ω,
R=R
1
+R
2
+R
3
i.e.
R1 =ρl
=10
Ω
= 5+10+15 = 30 Ω
A
∴ The current flowing through the circuit (I)
ρ=10A
…(i)
V
)
l
= Potentialofpowersupply(
Total resistance of the circuit (R)
For second wire, length = l/ 4, area of cross-section = 2.5 A
12
l/ 4
10A
l
=
∴ Resistance, R
2
=
ρ
=
[from Eq. (i)]
30
2.5A l
4
×
2.5A
2
=
=
. A
=1Ω
5
So, the resistance of that wire is 1 Ω.
In series combination, the current flowing through each
resistor is equal to total current flowing through the circuit.
Example 3. Resistance of a metal wire of length 2 m is
Therefore, current flowing through each resistor is 0.4 A.
30 Ω at temperature 25°C. If the diameter of the wire is
∴Potential difference across first resistor,
0.6 mm, then what will be the resistivity of the metal at that
1
V =IR
1
=
V
temperature?
Potential difference across second resistor,
Sol. Given, length of wire, l = 2 m
V =IR
=
V
Resistance, R = 30 Ω , Temperature, T = 25°C
2
2
4
and potential difference across third resistor,
Diameter of wire, d =
0.6
mm
=
6
×10
m
V =IR
=
V
Resistivity of the wire, ρ = ?
3
3
We know that,
Example 5. Study the following electric circuit. Find the
V)
readings of (i) the ammeter and (ii) the voltmeter.
Current (I)
=Potentialdifference(
Resistance (
R)
+
-
V
We get the following results for the current
A
B
12
Current through 40 Ω resistor, I1
=
= 0.3 A
40
Also, I2 =
. A
+
-
(
)
12
-
A+
Current through 20 Ω resistor, I
=
= 06A
3V
K
3
20
Sol. In the given circuit, the resistance of 4 Ω and bulb resistance
∴Current, I = I + I
1
2
+I
3
=
0.3A
+
0.3A
+
0.6
A
of 2 Ω are connected in series, so equivalent resistance of the
= 1.2 A
circuit,
R=R +R
1
2 =4Ω+2Ω=6Ω
Example 7. In the given figure, R1 = 5 Ω, R2 = 10 Ω, R3
=
(i) Total current flowing in the circuit, (I)
15 Ω, R4 = 20 Ω, R5 = 25 Ω and a 15 V battery is
3
connected to the arrangement. Calculate
=Potentialdifference(V)
=
= 0.5A
Total resistance (R)
6
(i)
the total resistance in the circuit, and
In series combination, current flowing through each
(ii)
the total current flowing in the circuit.
component of the circuit is same and is equal to the total
R1
current flowing in the circuit. So, 0.5 A current will flow
through the ammeter, so its reading will be 0.5 A.
R2
(ii) Reading of voltmeter = Potential difference across 2 Ω
I
bulb
V = IR =0.5 × 2 = 1 V
+
15 V
A
[Q current flowing through the bulb is 0.5 A]
R3
-
Example 6. Two 40 Ω resistors and a 20 Ω resistor are all
R4
connected in parallel with a 12 V power supply. Calculate
(
)
R5
their effective resistance and the current through each
resistor. What is the current flowing through the supply?
Sol. Resistors R1 and R2 are in parallel.
Sol. Given, R1 = 40 Ω, R2 = 40 Ω, R3 = 20 Ω,
1
1
1
1
1
1
V =12V,R = ?, I,I ,I ,I
?
So,
=
+
=
+
Rʹ =10 Ω
1
2
3 =
Rʹ
R
1
R
2
Rʹ
5
10
3
+12V-
Similarly, R ,R
3
4
and R5 are in parallel
I
R1=40 Ω
I
1
1
1
1
1
1
1
I
1
=
+
+
=
+
+
3
Rʹʹ R R R
4
5
15
20
25
R2=40 Ω
I2
1
20+15+12
300
=
Rʹʹ =
Rʹ
300
47
I3
R3=20 Ω
Thus, the total resistance,
According to circuit, the three resistors are connected in
10
300
R = Rʹ + Rʹʹ =
+
=
3.33+6.38
=9.71
Ω
parallel combination, then effective resistance,
3
47
1
1
1
1
=
+
+
V
15
The total current, I
=
=
=1.54 A
R R
1
R
2
R
3
R
1
1
1
=
+
+
Example 8. Find the equivalent resistance of the following
40
40
20
circuit. Also, find the current and potential at each resistor.
1
+
1
+
2
4
1
=
=
=
1Ω
40
40
10
R2
R =10 Ω
So, the three resistors together have an effective resistance
R3
2Ω
3Ω
2Ω
of10 Ω. Each resistor has a potential difference of12 V across it.
A
B
R1
R4
R5
Because in parallel combination, the potential difference
across each resistance is equal to the total potential
+
-
difference applied on the combination.
9V
K
Sol. In the given circuit, R ,R
and R4 are in parallel
R2
2
3
I2
combination. As, currents through R ,R
2
3
and R4 are
different. So, their equivalent resistance R is
I3
R3
I
5
=
I
I=I1
R1
R2
I4
R4
R5
R3
+
-
I
K
A
B
R1
R4
R5
As R ,R
2
3
and R4 are in parallel combination, so potential
+
-
drop at all resistances will be same as 1 V.
9V
K
2
3
V =V =V =V
4
ʹ=
1V
1
1
1
1
=
+
+
V
2
Vʹ
1
Current through R2 , I
=
=
=
=1A
Rʹ
R
2
R
3
R
4
2
R
2
R
2
1
1
1
1
6
+
3
+
2
11
=
+
+
=
=
3
V Vʹ
1
1
2
3
6
6
Similarly,
I
=
=
=
= 0.5 A
3
6
3
R R
3
2
Rʹ =
Ω
11
V
4
Vʹ
1
and
I
4
=
=
=
= 0.33 A
Now, the given circuit can be redrawn as shown below
R
R
3
4
4
6/11 Ω
A
B
Example 9. An electric iron consumes energy at a rate
R1
R
5
of 880 W, when heating is at the maximum rate and 340 W,
9V
K
when the heating is at the minimum, the voltage is 220 V.
+
-
What are the current and the resistance in each case?
Now, R1,Rʹ and R5 are in series combination. As, current
Sol. Power, P = VI, Current, I = P / V
through R ,R
1
ʹ and
R
5
is same.
880
(i) When heating is at the maximum rate, I =
=
4A
So, equivalent resistance of the whole circuit is
220
6
V
220
R = R + Rʹ + R
2+
+
2
1
5 =
Resistance of the electric iron, R
=
=
=
55 Ω
11
I
4
22+
6+
22
50
=
=
Ω
340
11
11
(ii) When heating is at the minimum rate, I =
=1.54A
220
Now, total current flowing through the circuit,
V
220
9
99
Resistance of the electric iron, R
=
=
=14
Ω
I= V
=
=
≈2A
I
1.54
R
50 / 11
50
Current through R1 and R5 will be same as these are in
Example 10. An electric heater of resistance 500 Ω is
series combination and will be equal to the total current
connected to a mains supply for 30 min. If 15 A current
flowing through the circuit.
flows through the filament of the heater, then calculate the
1
I=I =I =
5
2A
heat energy produced in the heater.
Potential drop at R1 , V =I R
=2 ×2 =4V
Sol. Given, resistance of the filament, R = 500 Ω
1
1
1
Potential drop at R5 , V =I R
=2 ×2 =4V
Current, I =15 A
5
5
5
Now, potential drop at Rʹ , Vʹ can be calculated as
Time, t = 30 min = 30 × 60 = 1800 s
1
V = V + V + Vʹ
5
Heat produced, H = I2Rt
2
9 = 4 + 4 + Vʹ
=15
× 500 ×1800
Vʹ = 1 V
= 2025 ×105 J = 20.25 ×107 J
Chapter Practice
PART 1
4.
Specific resistance of a conductor increases on
increasing its temperature.
Objective Questions
(a) True
(b) False
(c) Can’t say
(d) Information insufficient
Multiple Choice Questions
5.
A cylindrical conductor of length l and uniform area
1.
Which one of the following is the correct set-up for
of cross-section A has resistance R. Another
studying the dependence of the current on the
conductor of length 2l and resistance R of the same
potential difference across a resistor?
(CBSE 2019)
material has area of cross-section
(CBSE 2020)
R
R
(a) A / 2
(b) 3A / 2
(c) 2A
(d) 3A
+
-
+
-
V
A
6.
The substance which have a higher value of
(a) A
(b)
V
resistance and small number of free electrons in it, is
+
+
+
-
+
-
called
(a) resistor
(b) poor conductor
+
V
(c) good conductor
(d) insulator
-
+
+
-
7.
What is the maximum resistance which can be made
V
A
1
using four resistors each of
(CBSE 2020)
2Ω?
R
R
(c)
A
(d)
(a) 2 Ω
(b)1Ω
+
(c) 2.5 Ω
(d) 8 Ω
+
-
+
-
8.
Three 2 Ω resistances are connected so as to make a
2.
A student carries out an experiment and plots the V-I
triangle. The resistance between any two vertices is
graph of three samples of nichrome wire with
(a) 6 Ω
(b) 2 Ω
resistances R ,R
1
2
and R3 respectively. Which of the
3
4
(c)
Ω
(d)
Ω
following is true?
4
3
R1
9.
Determine the equivalent resistance between points
R2
X and Y in the following circuit.
3!
R3
3!
3!
3!
V(volt)
(a) R
=
R =R
(b) R >R >R
1
2
3
1
2
3
X
Y
(c) R
3
>
2
R >R
1
(d) R
2
>
3
R >R
1
(a) 5 Ω
(b)12 Ω
3.
The resistivity does not change, if
(NCERT Exemplar)
(c) 9 Ω
(d) 6 Ω
(a) the material is changed
10.
The filament of bulb is made up of
(b) the temperature is changed
(a) copper
(b) tungsten
(c) the shape of the resistor is changed
(c) tin
(d) lead
(d) Both material and temperature are changed
11.
The current flowing through a wire of resistance 2 Ω
17. Assertion The connecting wires are made of copper.
varies with time as shown in the given figure. The
Reason The electrical conductivity of copper is high.
amount of heat produced (in J) in 3 s would be
18. Assertion When the resistances are connected
3
end-to-end consecutively, they are said to be in series.
B
C
2
Reason In case the total resistance is to be
H I
decreased, then the individual resistances are
1
A
D
connected in parallel.
t (s)
0
G J
-1
19. Assertion The fuse is placed in series with the device.
-2
Reason Fuse consists of a piece of wire made of a
E
F
–3
metal or an alloy of appropriate melting point.
(a) 2 J
(b) 18 J
20. Assertion The 200 W bulbs glow with more
(c) 28 J
(d) 10 J
brightness than 100 W bulbs.
12.
The rate at which energy is delivered by a current is
Reason A 100 W bulb has more resistance than
determined by
200 W bulb.
(a) heat
(b) electric power
Case Based MCQs
(c) potential difference
(d) work
13.
In an electrical circuit three incandescent bulbs A, B
21.
Read the following and answer questions from (i) to (v)
and C of rating 40 W, 60 W and 100 W, respectively
given below
are connected in parallel to an electric source. Which
The relationship between potential difference and
of the following is likely to happen regarding their
current was first established by George Simon Ohm
brightness?
called Ohm’s law. An electric circuit is shown below
(a) Brightness of all the bulbs will be the same
to verify Ohm’s law.
(b) Brightness of bulb A will be the maximum
+
V-
Voltmeter
(c) Brightness of bulb B will be more than that of A
A
(d) Brightness of bulb C will be less than that of B
Conductor
Connecting
14.
An electric kettle consumes 1 kW of electric power
wires
Sliding contact
C
of rheostat
when operated at 220 V. A fuse wire of what rating
+
-
B
S
Rh
must be used for it?
(NCERT Exemplar)
Battery
Switch
Rheostat
(a) 1 A
(b) 2 A
(c) 4 A
(d) 5 A
Although Ohm’s law has been found valid over a
15.
LED indicator of a TV in your house operates at
large class of materials, there do exist metals and
0.75 V and 100 mA. Then its power is
devices used in electric circuits where the
(a) 75 mW
(b) 1.00 mW
(c) 0.75 mW
(d) 7.5 mW
proportionality of V and I does not hold.
(i) Materials which follow Ohm’s law are
Assertion-Reasoning MCQs
(a) ohmic conductors
(b) non-ohmic conductors
(c) insulators
(d) superconductors
Direction (Q. Nos. 16-20) Each of these questions
contains two statements Assertion (A) and Reason (R).
(ii) For insulator at room temperature, the graph
between V and Iis given. Which one is correct?
Each of these questions also has four alternative
choices, any one of which is the correct answer. You have to
I
I
select one of the codes (a), (b), (c) and (d) given below.
(a) Both A and R are true and R is the correct
(a)
(b)
explanation of A.
(b) Both A and R are true, but R is not the correct
V
explanation of A.
O
V
O
(c) A is true, but R is false.
(d) A is false, but R is true.
I
I
16. Assertion Longer wires have greater resistance and
the smaller wires have lesser resistance.
(c)
(d)
Reason Resistance is inversely proportional to the
length of the wire.
V
V
O
O
(iii) The slope of V - I graph (V on x-axis and Ion
PART 2
y-axis) gives
(a) charge
Subjective Questions
(b) reciprocal of resistance
(c) resistance
(d) reciprocal of charge
Short Answer Type Questions
(iv) By increasing the voltage across a conductor, the
1. State the law which gives the relationship between
(a) current will decrease
current and potential difference. Define the unit of
(b) resistance will increase
resistance.
(c) resistance will decrease
(d) current will increase
2. Define resistance. Give its SI unit.
(CBSE 2019)
(v) When a 9 V battery is connected across a
3. The values of current I flowing in a given resistor for
conductor and the current flows is
. A, the
the corresponding values of potential difference V
resistance is
across the resistor are as given below
(a) 90 Ω
(b) 9 Ω
(c)
. Ω
(d) 900 Ω
V (volts)
0.5
1.0
1.5
2.0
2.5
3.0
4.0
5.0
22.
Read the following and answer the questions from (i)
I (amperes)
0.1
0.2
0.3
0.4
0.5
0.6
0.8
1.0
to (v) given below
Plot a graph between V and I and also calculate the
The electrical energy consumed by an electrical
resistance of that resistor.
(CBSE 2018)
appliance is given by the product of its power rating
4. Why are coils of electric toasters and electric irons
and the time for which it is used. The SI unit of
electrical energy is Joule (as shown in figure).
made of alloy rather than a pure metal?
(NCERT)
I
5.
(i) List the factors on which the resistance of a
+
conductor in the shape of a wire depends.
(ii) Why are metals good conductors of electricity,
Voltage
R
Power
whereas glass is a bad conductor of electricity?
Give reason.
-
(iii) What type of material is used in electrical heating
devices? Give reason.
(CBSE 2018)
Actually, Joule represents a very small quantity of
energy and therefore it is inconvenient to use where
6.
I
A
a large quantity of energy is involved.
(i) The SI unit of electric energy per unit time is
(a) joule
(b) joule-second
12 V
R1=4 Ω
R2
(c) watt
(d) watt-second
(ii) Kilowatt-hour is equal to
(a) 3.6
×
104
J
(b) 3.6
×
106
J
B
(c) 36
×
106
J
(d) 36
×
104
J
(iii) The energy dissipated by the heater is E. When
A student has two resistors 2 Ω and 3 Ω. She has to put
the time of operating the heater is doubled, the
one of them in place of R2 as shown in the circuit.
energy dissipated is
The current that she needs in the entire circuit is
(a) doubled
(b) half
exactly 9 A.
(c) remains same
(d) four times
Show by calculation which of the two resistors she
(iv) The power of a lamp is 60 W. The energy
should choose.
consumed in 1 minute is
7. A metal wire has diameter of 0.25 mm and electrical
(a) 360 J
(b) 36 J
resistivity of 0.8
×
108
Ω-m.
(c) 3600 J
(d) 3.6 J
(i) What will be the length of this wire to make a
(v) Calculate the energy transformed by a 5 A current
resistance 5 Ω?
flowing through a resistor of 2 Ω for 30 minutes.
(ii) How much will the resistance change, if the
(a) 40 kJ
(b) 60 kJ
(c) 10 kJ
(d) 90 kJ
diameter of the wire is doubled?
8.
Redraw the given circuit, putting in an ammeter to
15.
In an electrical circuit, two resistors of 2 Ω and 4 Ω
measure the current through the resistors and a
are connected in series to a 6 V battery. Find the heat
voltmeter to measure the potential difference across
dissipated by the 4 Ω resistor in 5 s. (NCERT Exemplar)
12 Ω resistor. What would be the readings in
16.
Why does the cord of an electric heater not glow
ammeter and voltmeter?
(NCERT)
while heating element does?
(NCERT)
6V
+
-
17.
Why fuse are used in electrical circuits?
18.
Define the SI unit of electric power. What is the
K
commercial unit of electrical energy?
12 Ω
19.
The electric power consumed by a device may be
calculated by using either of the two expressions
9.
What is the reason of connecting electrical appliances
P =I2R orP = V2/R.
in parallel combination in household circuit?
The first expression indicates that the power is
10.
What is (i) the highest and (ii) the lowest total
directly proportional to R, whereas the second
resistance which can be secured by combinations
expression indicates inverse proportionality. How
of four coils of resistances 4 Ω, 8 Ω, 12 Ω and 24 Ω?
can seemingly different dependence of P on R in
(NCERT)
these expressions be explained?
11.
Consider the circuit diagram as given below
20.
Three 2 Ω resistors, A, B and C are connected as
R5=3Ω
+
-
shown in figure. Each of them dissipates energy
and can withstand a maximum power of 18 W
without melting. Find the maximum current that can
A
R3=3Ω
flow through the three resistors?
(NCERT Exemplar)
=3Ω
K
I
B
I
R1= 3 Ω
R2
=3Ω
A
C
If R =R =R =R =R
=
3
Ω, then find the
1
2
3
4
5
equivalent resistance of the circuit.
12.
With the help of suitable circuit diagram prove that
21.
An electric geyser rated 1500 W, 250 V is connected
the reciprocal of the equivalent resistance of a group of
to a 250 V line mains. Solve
resistances joined in parallel is equal to the sum of
(i) the electric current drawn by it.
the reciprocals of the individual resistances.(CBSE 2019)
(ii) energy consumed by it in 50 h.
(iii) cost of energy consumed, if each unit costs ` 6.
13.
A battery E is connected to three identical lamps P, Q
and R as shown in figure. Initially, the switch S is kept
Long Answer Type Questions
open and the lamp P and Q are observed to glow with
same brightness. Then, switch S is closed.
22. In the given circuit, A, B, C and D are four lamps
connected with a battery of 60 V.
P
Q
60 V
+
S
E
-
3A
A
4A B 5A C 3A D
R
Analyse the circuit to answer the following questions.
How will the brightness of glow of bulbs P and Q
(i) What kind of combination are the lamps arranged in
change? Justify your answer.
(series or parallel)?
14.
(i) Write Joule’s law of heating.
(ii) Explain with reference to your above answer, what
(ii) Two lamps, one rated 100 W, 220 V and the other
are the advantages (any two) of this combination of
60 W, 220 V are connected in parallel to electric
lamps?
main supply.
(iii) Explain with proper calculations which lamp glows
Find the current drawn by two bulbs from the line,
the brightest.
if the supply voltage is 220 V.
(CBSE 2018)
(iv) Find out the total resistance of the circuit.
23. Find the equivalent resistance of the following circuit.
Case Based Questions
Also, find the current and potential at each resistor.
Read the following and answer the questions from (i)
28.
1Ω
to (v) given below
R2
Several resistors may be combined to form a
network. The combination should have two end
R
3
2Ω
3Ω
2Ω
points to connect it with a battery or other circuit
A
B
R1
R4
R
elements. When the resistors are connected in series,
5
the current in each resistor is same but the potential
+
-
9V
K
difference is different in each resistor.
When the resistors are connected in parallel, the
24.
(i) State Ohm’s law.
voltage drop across each resistor is same but the
(ii) How is an ammeter connected in an electric circuit?
current is different in each resistor.
(iii) The power of a lamp is 100 W. Find the energy
(i) What do you mean by complex circuit?
consumed by it in 1 min.
(ii) In the graph, it shows the resistance in series and
(iv) A wire of resistance 5Ω is bent in the form of a
parallel for two identical wires. Which of the
closed circle. Find the resistance between two
points at the ends of any diameter of the circle.
following denotes series combination and parallel
combination, individually?
25. An electric lamp of resistance 20 Ω and a conductor
B
of resistance 4 Ω are connected to a 6 V battery as
shown in the circuit given below.
A
I
V
(iii) What is the equivalent resistance of the circuit
+
-
K
given below?
A
-
+
6V
Calculate
B
A
(i) the total resistance of the circuit.
(ii) the current through the circuit.
(iii) the potential difference across the
(a) electric
(iv) What is minimum effective resistance?
lamp and (b) conductor.
(v) When three resistors of resistances R,2Rand 3R
(iv) the power of the lamp.
(CBSE 2019)
are connected in series then, how will be the
26.
(i) How should two resistors, with resistances R1(Ω)
value of current gets affected in each resistor by
andR2(Ω)be connected to a battery of e.m.f. Vvolts
applying a voltage V across the circuit?
so that the electrical power consumed is minimum?
29. Read the following and answer the questions from (i)
(ii) In a house, 3 bulbs of 100 watt each are lighted for
to (v) given below
5 hours daily, 2 fans of 50 watt each are used for
10 hours daily and an electric heater of 1.00 kWh
A cell or a battery is the source of electrical energy.
is used for half an hour daily. Calculate the total
Due to the chemical reactions inside them a
energy consumed in a month of 31 days and its
potential difference is setup which is responsible for
cost at the rate of ` 3.60 per kWh.
the flow of current through any electrical circuit.
27.
(a) Define power and state its SI unit.
So, to maintain this flow, the source continuously has
to provide the energy. But only a part of this energy
(b) A torch bulb is rated 5V and 500 mA. Calculate its
helps in maintaining the current consumed into
(i) power
useful work.
(ii) resistances
Rest of it may be consumed in the form of heat by
(iii) energy consumed when it is lighted for 21
hours.
raising the temperature of the appliances.
2
(i) How heat produced in a resistor is related to current
It showed an electric circuit in which 3 resistors
having resistor R ,R
and R3 respectively are
flowing in that resistor?
1
2
(ii) Give two practical application of heating effect of
joined end to end i.e in series.
current.
While the combination of the resistors in which
(iii) Which type of energy is transformed into heat energy?
3 resistors connected together which point X
(iv) An electric iron of resistance 25 Ω takes a current of
and Y are said to be parallel.
7 A. Calculate the heat developed in 0.5 min.
(i) Calculate the potential difference across a
(v)
200 J of heat is produced in 10 s in a 5 Ω resistance.
series combination of resistors.
Find the potential difference across the resistor.
(ii) What is the value of current in a series
combination?
30. Read the following and answer questions from (i) to (v)
(iii) Write the formula of electrical energy
given below
dissipated in the resistor.
In resistance for a system of the resistor, there are two
(iv) If 200 resistors, each of value 0.2 Ω are
methods of joining the resistors together as shown below
connected in series, what will be the resultant
L
R
3
M
resistance?
R2
R
R2
R3
X
Y
(v) What will be the effective resistance shown in
1
P R1
Q
figure below?
V
S
T
+
V
-
A
Rh
I
I
K
+
-
K
+
-
-
A
+