Italaqi Barqiat Class 8 PDF Download – Punjab Board (PCTB)

Italaqi Barqiat (Applied Electricity) for Class 8 is the official practical/skills textbook published by the Punjab Curriculum and Textbook Board (PCTB), Lahore, in Urdu medium. It is part of the official syllabus for Class 8 students and is built entirely around 20 hands-on practical jobs, from wiring simple circuits to studying meters, motors and household appliances, instead of regular theory chapters.

For Class 8 students taking this elective, each job pairs a real workshop exercise with short questions at the end, so this page breaks down every job with a clear explanation and its own set of important questions. It is a useful way to revise the practical steps and underlying concepts, such as Ohm’s Law or how a fuse works, before a practical exam or viva.

Book Overview

Class	8
Subject	Italaqi Barqiat (Applied/Practical Electricity)
Board	Punjab Board (PCTB, Lahore)
Total Jobs	20
Total Pages	88
Medium	Urdu
Format	PDF (Free Download)

Job List

Job 1: Observation of the Chemical Effects of Electric Current (کیمیائی اثرات)

This job demonstrates how electric current can be produced through a chemical reaction, using a simple homemade cell. Students dilute sulphuric acid in water inside a beaker, then insert zinc and copper strips without letting them touch, wiring the strips through a switch to a small 1.5V bulb. Turning the switch on lights the bulb, showing current flow, while holding a compass needle near the wire reveals a magnetic deflection that confirms current is flowing. The job introduces ions, electrolytes, and how a potential difference between the zinc and copper electrodes drives current through the circuit.

Important Questions:

• What are ions, and how are electrolytes formed? Ions are charged particles formed when a substance breaks up in solution; a substance that produces ions in solution is called an electrolyte.
• Give examples of common acids. Hydrochloric acid, nitric acid and sulphuric acid, along with acetic acid found in vinegar and citric acid found in lemon juice.
• How should a concentrated acid be safely diluted? It should be added drop by drop into water while stirring with a glass rod, never by pouring water into the acid.
• What is polarization in a simple voltaic cell? Hydrogen bubbles collect on the copper electrode, reducing its effective surface area and lowering the potential difference, which reduces the current over time.

Job 2: Observation of Safety Devices (حفاظتی آلات)

This job examines the safety devices that protect household electrical circuits from damage. Students build a simple test circuit with a dry cell, switch, fuse holder and bulb, then check continuity before and after removing the fuse wire, observing how a blown fuse breaks the circuit. The exercise is repeated with a cartridge-type fuse and then with a circuit breaker, where pressing a button restores the connection after it trips. Students learn how a fuse wire’s low melting point and a circuit breaker’s bimetallic strip both cut off current before it damages costly appliances.

Important Questions:

• How does a fuse work? When current exceeds a safe limit, the fuse wire heats up and melts, breaking the circuit before it damages connected appliances.
• What is the difference between fuse wire and ordinary wire? Fuse wire has high resistance and a low melting point so it melts quickly under excess current, while ordinary wire has a much higher melting point.
• Describe the construction of a cartridge-type fuse. A fuse wire sealed inside a glass tube with metal caps on both ends, fitted into a special holder; a blown cartridge fuse is simply replaced.
• How does a circuit breaker work? A bimetallic strip bends under excess current and breaks contact, cutting off the circuit, and it can be reset with a button, unlike a fuse.

Job 3: Verification of Ohm’s Law (اوہم کا قانون)

This job verifies Ohm’s law by building a circuit with a dry cell, switch, and a bulb acting as a resistor, with an ammeter connected in series and a voltmeter connected in parallel. Current and voltage readings are recorded as the number of cells is increased from one to three, and the ratio V/I is calculated each time, showing it stays constant and equals the circuit’s resistance in ohms. A second part of the job varies the length, thickness and material of copper, iron and aluminium wires to show how resistance depends on each of these factors.

Important Questions:

• State Ohm’s law. Current between two points is directly proportional to the potential difference across them, provided other conditions stay constant, expressed as V = IR.
• What factors does resistance depend on? A conductor’s length, cross-sectional area, and the material it is made of.
• How is an ammeter connected compared to a voltmeter? An ammeter is connected in series to measure current, while a voltmeter is connected in parallel to measure voltage.
• If a wire is made longer at the same thickness, how does resistance change? It increases, since resistance is directly proportional to length.

Job 4: Observation of Series and Parallel Circuits (سیریز اور پیرلل سرکٹ)

This job compares how bulbs behave when wired in series versus in parallel on a wooden board. In the series arrangement, bulbs are connected end to end; removing one bulb breaks the circuit and turns off all the others, and brightness dims as more bulbs are added because total resistance rises. In the parallel arrangement, each bulb has its own path to the battery, so removing or adding bulbs does not affect the brightness of the rest, which is how household wiring is done.

Important Questions:

• What happens to bulb brightness in a series circuit as more bulbs are added? Brightness decreases with each additional bulb, since total resistance increases while current drops.
• What happens if one bulb is removed from a series circuit? The circuit becomes incomplete and all the other bulbs go out.
• What happens if one bulb is removed from a parallel circuit? The remaining bulbs continue to glow at the same brightness.
• How are ammeters and voltmeters connected in a circuit? An ammeter in series to measure current, a voltmeter in parallel to measure voltage.

Job 5: Use of the Energy Meter (انرجی میٹر)

This job explores the construction, installation and reading of a household energy meter. Opening the meter reveals a pressure coil on a large magnet and a current coil on a smaller magnet, whose differing magnetic fields spin a disc connected through gears to the dial counters. Students learn to wire the meter with its current coil in series and pressure coil in parallel with the supply, and to calculate monthly electricity consumption by subtracting the start-of-month reading from the end-of-month reading.

Important Questions:

• What is the energy meter used for? It measures the electrical energy, in kilowatt-hours, a household consumes, which the utility uses to calculate the bill.
• Describe the meter’s main parts. A current coil on a small magnet and a pressure coil on a large magnet, linked through gears to the counter dials.
• How does the disc rotate? The difference between the two coils’ magnetic fields makes the disc beneath them spin.
• What is the benefit of the energy meter? It lets the supply company bill based on actual usage, and lets consumers see how much power they use.

Job 6: Use of the Wire Gauge (وائر گیج)

This job teaches students to measure a wire’s gauge (size) using a wire-gauge tool. Students strip a wire’s insulation without scratching the conductor and seat it into the gauge’s slots to find which slot it fits most easily, matching the number against a diameter chart. The job also distinguishes non-flexible house-wiring cable from flexible appliance cable, and explains cable-size notation with safe current limits for common sizes.

Important Questions:

• How many types of wires are commonly used? Two types: non-flexible (rigid) wires and flexible wires.
• What precaution is needed when using a wire gauge? The conductor must be inserted gently into the slots without forcing it.
• What is the difference between flexible and non-flexible wires? Non-flexible wires use thicker, harder strands for fixed house wiring, while flexible wires use thinner, bendable strands for movable appliances.
• Why does thicker cable carry more current safely? A larger cross-sectional area lowers resistance, letting it carry higher current without overheating.

Job 7: Tube Light Circuit through Batten Wiring (بیٹن وائرنگ)

Students wire a complete tube-light circuit on a practice board: mounting the tube-holder strip, ceiling rose, switch and choke, then connecting the leads through the fuse and switch to the ceiling rose, choke, tube socket and starter. The core concept is how the choke’s coiled winding gives it high inductive reactance, limiting current, while the starter briefly heats the tube’s cathodes and then cuts out, letting the choke’s voltage surge ignite the tube.

Important Questions:

• Is the choke connected in series or in parallel? The choke is connected in series with the tube and starter.
• What is the key difference between bulb light and tube light? Tube light is produced by fluorescence and gives cool, soft light, while bulb light comes from a heated filament and is warmer and more tiring to the eyes.
• Describe the working of the starter. Two bimetallic strips heat and briefly close the circuit to heat the tube’s cathodes, then cool and separate, letting the choke’s voltage spike ignite the tube.
• Describe the construction of the choke. A thick coiled copper wire wound around a soft-iron core, giving it high inductive reactance to control AC current.

Job 8: Tube Light, Bulb and Socket Circuit (ٹیوب لائٹ، بلب اور ساکٹ)

Building on Job 7, this exercise wires a combined board circuit controlling a tube light, a bulb and a socket, each through its own switch, using a junction box to distribute the supply. Beyond the wiring steps, the job covers practical knowledge: grades of PVC-insulated wire, the range of switch types (tumble, rocker, flush, ceiling pull-cord, push-button, two-way, dimmer), and the difference between two-pin and three-pin (earthed) sockets.

Important Questions:

• How many types of switches are there? Several, including tumble/lever, rocker, flush, ceiling pull-cord, push-button, two-way, and dimmer switches.
• What are the types of sockets? Two-pin sockets carrying live and neutral only, and three-pin sockets which add an earth pin.
• What does a switch do in a circuit? It completes or breaks the circuit’s current path.
• Why is the wire for an iron or hot plate covered with a cloth braid? These appliances get very hot, so the cloth braid gives extra heat resistance where plain PVC would be unsafe.

Job 9: Determining Polarity (پولیرٹی معلوم کرنا)

This job teaches two related skills: building a simple test lamp to check wire polarity, and using a megger to test wiring continuity and insulation resistance. The phase wire sits at 220V while the neutral and earth sit at 0V, so the test lamp lights only when its leads bridge a real potential difference (phase to earth) and stays dark when both leads touch equal-potential wires, such as neutral to earth. This is how the phase wire is identified among household wiring conductors.

Important Questions:

• Why does the test lamp light between earth and the phase wire? Because the phase wire is at 220V and earth is at 0V, and this potential difference drives current through the bulb.
• Why does the bulb not light between earth and neutral? Both are at 0V potential, so there is no potential difference to drive current.
• What is a megger? A hand-cranked instrument that measures insulation resistance, generating about 500V internally through its earth and line terminals.
• Why do we determine polarity in household wiring? To find out which wire is the phase (220V) and which is the neutral (0V), essential for safe wiring.

Job 10: Study of the Structure of the Ammeter (ایمیٹر کی ساخت)

Students dismantle a common Weston-type ammeter connected in series in a bulb circuit, examining its scale, permanent magnet, coil, spring-mounted needle, and a low-resistance shunt wired in parallel with the coil. Current through the coil creates a magnetic field that reacts against the permanent magnet, rotating the needle proportional to current, while the shunt diverts most of the circuit’s current so only a small, safe fraction passes through the coil.

Important Questions:

• Why must an ammeter be connected in series, never in parallel? Its very low resistance would let excessive current flow through it in parallel and burn it out.
• What is an ammeter used for? To measure the amount of electric current flowing through a circuit.
• Why does the ammeter’s needle rotate when current flows? Current through the coil creates a magnetic field that reacts against the fixed magnet, rotating the needle until the current stops.
• What is a shunt, and what does it do? A low-resistance wire in parallel with the coil that diverts most current around it, letting the meter safely measure larger currents.

Job 11: Study of the Structure of the Voltmeter (وولٹ میٹر کی ساخت)

This job studies the internal structure of a common Weston-type voltmeter, which measures the potential difference across a load. Opening the casing shows it is built almost exactly like an ammeter, except a high-resistance multiplier wire is placed in series with the coil instead of a low-resistance shunt in parallel. Because of this, the voltmeter is always wired in parallel across the load’s terminals, and its needle deflection shows the voltage needed to push the small operating current through the coil.

Important Questions:

• What is the key structural difference between a voltmeter and an ammeter? A voltmeter has a high-resistance multiplier wire in series with the coil, an ammeter has a low-resistance shunt in parallel.
• Is a voltmeter connected in series or parallel? Always in parallel across the load’s terminals.
• What does the multiplier resistor do? It is a high-resistance wire in series with the coil that limits coil current and lets the meter read different voltage ranges.
• What does the voltmeter’s needle reading represent? The potential difference needed to drive the small current through the coil, equal to the voltage across the load.

Job 12: Study of the Structure of the Lamp (لیمپ کی ساخت)

This job dissects an ordinary bulb, showing why bulbs are sealed with nitrogen and argon instead of air. Inside, current enters through a tungsten lead fused to the glass, passes through a fine coiled filament that glows from its high resistance, and exits through a second lead. The job then compares this to a fluorescent tube, where heated electrodes strike mercury vapour and argon to produce ultraviolet light that makes a phosphor coating glow, giving more even, efficient light than a bulb.

Important Questions:

• Why is a coiled tungsten wire used as the filament? Its high resistance makes it glow white-hot when current passes through it, producing light.
• What properties make tungsten suitable for the lead-in wires? It can fuse with glass to form an airtight seal and is an excellent conductor.
• Why is the bulb filled with nitrogen and argon instead of air? These inert gases do not react with the hot filament, whereas oxygen would burn it out.
• How does a fluorescent tube produce light differently from a bulb? Heated electrodes strike mercury vapour and argon to produce ultraviolet rays that make the phosphor coating glow.

Job 13: Earthing (ارتھنگ)

This job builds a plate-earthing system: a copper plate is welded to an iron rod and buried in a pit deep enough to reach moist soil, packed in a charcoal-and-salt paste that lowers the resistance between the plate and the earth. Since current always follows the path of least resistance, a properly earthed appliance sends any leakage current from a damaged live wire safely into the ground rather than through a person touching its casing. The job also surveys rod, strip, and pipe earthing methods for different ground conditions.

Important Questions:

• Why is earthing necessary for electrical appliances? It diverts leaking current into the ground instead of through a person who touches the appliance, preventing shock.
• Why does leakage current flow toward the earth connection? Current always takes the path of least resistance, and a good earth connection offers much lower resistance than the human body.
• How is a basic plate-earthing system installed? A copper plate welded to an iron rod is buried in a pit reaching moist soil and packed with a charcoal-and-salt paste.
• What other earthing methods exist besides the plate method? Pointed rods joined end to end, a copper strip buried in a trench, or a galvanized pipe inserted into a drilled hole.

Job 14: Generator Study (جنریٹر کا مطالعہ)

This job demonstrates the working principle of a generator: a coil connected to a galvanometer shows current only while a magnet is moved into or out of it, proving current is induced only while the magnetic field is actually changing. A generator has two essential parts, a rotating armature carrying coils and a magnetic field system, one of which must keep turning to sustain continuous induced current. The job also examines the galvanometer, and how adding resistance converts it into a voltmeter or ammeter.

Important Questions:

• What is the basic principle a generator works on? Whenever the magnetic field linked with a coil changes, current is induced, continuing only as long as the field keeps changing.
• What are the two main parts of a generator? An armature carrying coils and a magnetic field system, one of which must rotate relative to the other.
• What is a galvanometer used for? A sensitive instrument used to detect and measure very small electric currents.
• How is a galvanometer turned into a voltmeter or ammeter? A large series resistance makes a voltmeter, a small parallel resistance makes an ammeter.

Job 15: DC Generator and AC Generator (ڈی سی اور اے سی جنریٹر)

This job opens both a DC generator and an AC generator (alternator) to compare their parts, including the mica-insulated commutator segments that convert the coils’ naturally alternating current into one-directional current, carbon brushes, and a cooling fan. It then contrasts this with the alternator, where the armature winding is fixed on the stator while the magnetic poles rotate on the rotor, so the induced current keeps alternating and no commutator is needed.

Important Questions:

• How does a DC generator make its current flow in one direction? A commutator rectifies the naturally alternating induced current into one-directional current.
• What is the role of the commutator? It collects the alternating current from the armature windings and delivers it to the brushes as one-directional current.
• What is the key difference between a DC generator and an alternator? In a DC generator the armature rotates while the field stays still; in an alternator the field rotates and there is no commutator.
• Why does a generator need a cooling system? Current flow and friction produce heat that can damage insulation, so vents and a fan circulate air to carry it away.

Job 16: DC Motor (ڈی سی موٹر)

This job examines the construction and working of a simple DC motor, built from a rotor mounted on a shaft that spins inside a magnetic field created by two field-magnet poles. Current passed through coils wound on the armature produces a force on the conductor, and the commutator and brushes reverse the current direction at each half-turn so the armature keeps rotating in the same direction. The job also covers the motor’s main parts and its wiring types and uses.

Important Questions:

• What is the basic principle of a DC motor? A current-carrying conductor in a magnetic field experiences a force, which produces continuous rotation of the armature.
• What are the main parts of a DC motor? Yoke, stator, rotor/armature, commutator, brushes, and a cooling arrangement.
• How many types of motors are there based on internal wiring? Three: series-wound, shunt-wound, and compound-wound motors.
• What are common uses of an electric motor? Moving machine parts in factories and running devices such as tube-well pumps.

Job 17: Observation of the Electric Heater (برقی ہیٹر)

This job has students disassemble a rod-type electric heater, removing the spring-wound element from its ceramic rod and measuring its resistance with an ohmmeter, before reassembling and testing it live. It explains how a heater converts current into heat through a high-resistance Nichrome wire, and surveys reflector heaters, fan heaters, and ceramic hot-plate cookers. It also explains why the element is coiled: coiling packs a longer, higher-resistance wire into less space while raising heat output.

Important Questions:

• Why is a coiled wire used in a heater? Coiling fits a long, high-resistance wire into a small space and adds an inductive effect that increases heat output.
• What parts does an ordinary heater have? A heating element, a ceramic rod, a reflector, and terminals connecting it to the supply.
• What is the function of the reflector? A polished metal sheet behind the element that reflects heat toward the user so less is wasted.
• How does resistance relate to heat produced? A higher resistance element produces more heat for the same current.

Job 18: Observation of the Electric Iron (استری)

This job walks students through fully disassembling a household electric iron into its handle, flat-wire heating element, and metal hot plate. Once opened, students examine the flat Nichrome-wire element embedded in mica sheets and learn that mica is an electrical insulator but a good heat conductor, so it keeps current away from the metal plate while still letting the element’s heat pass through and warm it. The iron is then reassembled and tested live.

Important Questions:

• What are the main visible parts of an iron? The handle, the hot plate, and the outer cover.
• How is an iron opened for inspection? Removing the handle’s back screw, then the nameplate and screws underneath to separate the handle and cover from the hot plate.
• What is the handle made of, and what does insulating mean? An insulating material, meaning one that does not allow electric current to pass through it, keeping the user safe from shock.
• Why is the iron’s element embedded in mica? Mica does not conduct electricity but does conduct heat, so it stops current from reaching the metal plate while letting the heat through.

Job 19: Comparing the Iron’s Element and the Heater’s Element (استری اور ہیٹر کے ایلیمنٹ)

This job has students open both a heater and an iron to compare their heating elements directly. The heater’s element is a round Nichrome wire wound into an open spring around a ceramic rod, left uncovered so heat reaches the user by radiation, whereas the iron’s element is a flat Nichrome wire wound between layers of mica and bolted flat against the iron’s metal plate. The job explains why mica insulates the iron’s element electrically while still conducting its heat, and notes that element wattage depends on wire length.

Important Questions:

• What is the main difference between the iron’s and heater’s elements? The heater’s element is a round wire wound into an open spring; the iron’s is a flat wire between layers of mica bolted flat against the plate.
• Why is the iron’s element kept inside mica? Mica insulates electrically but conducts heat well, and has a very high melting point.
• What is the usual wattage of a single-rod heater element? About 1000 watts.
• What does wattage depend on? The length of the resistance wire used, with more wire giving higher wattage.

Job 20: Observation of the Electric Kettle (بجلی کی کیتلی)

This job has students disassemble an electric kettle to study its sealed, pipe-shaped heating element and wiring. They examine how the element’s high-resistance wire sits inside a copper tube packed with magnesium oxide, which keeps the wire from touching the tube directly while still conducting its heat outward so the water heats quickly without the element ever contacting the water. Students also wire up matching plug sockets, check the circuit’s continuity with a megger, then fill the kettle with water and test it live.

Important Questions:

• What is a sealed element made of? A high-resistance heating wire enclosed inside a copper pipe so it can heat water without the bare wire touching it.
• What is packed inside the pipe of a sealed element, and why? Magnesium oxide, which keeps the wire from touching the pipe while still conducting heat well.
• What happens if a sealed element is heated without water around it? It will burn out, since it is built to work only while submerged in water.
• What are the female and male sockets in this circuit? The female socket is the fixed connector on the kettle, and the male plug has matching pins that connect it to the supply cord.

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Who Should Read This

This book is for Class 8 students following the Punjab Board (PCTB) syllabus who take Italaqi Barqiat as an elective. It is especially useful for students preparing for the practical exam or viva, since it walks through every job’s apparatus, procedure and key questions.

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Applicable Boards

This book is published mainly for Punjab Board (PCTB) Class 8 students. Students from other boards offering a similar practical electricity elective can also use it as a reference.

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