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    Chapter 2

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    أبوسوار هندسة
    This document summarizes 17 problems from chapter 2 of an electrical circuits theory and technology textbook. The problems cover topics such as Ohm's Law, power, energy, resistance, current, voltage, cost of electricity, and selecting appropriate fuses. They involve calculating values like resistance, current, voltage, power, energy, and cost based on information provided, such as wiring diagrams, appliance power ratings, current, voltage, time of use. The goal is to practice applying core electrical concepts to example circuits and devices.

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    Chapter 2

    Uploaded by

    أبوسوار هندسة
    99 views2 pages
    This document summarizes 17 problems from chapter 2 of an electrical circuits theory and technology textbook. The problems cover topics such as Ohm's Law, power, energy, resistance, current, voltage, cost of electricity, and selecting appropriate fuses. They involve calculating values like resistance, current, voltage, power, energy, and cost based on information provided, such as wiring diagrams, appliance power ratings, current, voltage, time of use. The goal is to practice applying core electrical concepts to example circuits and devices.

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    Problems of chapter 2 of electrical circuits theory and technology book .

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    This document summarizes 17 problems from chapter 2 of an electrical circuits theory and technology textbook. The problems cover topics such as Ohm's Law, power, energy, resistance, current, voltage, cost of electricity, and selecting appropriate fuses. They involve calculating values like resistance, current, voltage, power, energy, and cost based on information provided, such as wiring diagrams, appliance power ratings, current, voltage, time of use. The goal is to practice applying core electrical concepts to example circuits and devices.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    99 views2 pages

    Chapter 2

    Uploaded by

    أبوسوار هندسة
    This document summarizes 17 problems from chapter 2 of an electrical circuits theory and technology textbook. The problems cover topics such as Ohm's Law, power, energy, resistance, current, voltage, cost of electricity, and selecting appropriate fuses. They involve calculating values like resistance, current, voltage, power, energy, and cost based on information provided, such as wiring diagrams, appliance power ratings, current, voltage, time of use. The goal is to practice applying core electrical concepts to example circuits and devices.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
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    Problems of chapter 2 of electrical circuits theory and technology book .

    2.12 Further problems on the introduction to electric circuits

    1- In what time would a current of 10 A transfer a charge of 50 C?


    [5 s]
    2 A current o
    [3600 C]
    3- How long must a current of 100 mA flow so as to transfer a charge of 80 C?
    [13 min 20 s]

    Ohms law
    4- The current flowing through a heating element is 5 A when a p.d. of 35 V is applied across it. Find the
    resistance of the element.
    [7 ohm ]
    5- A 60 W electric light bulb is connected to a 240 V supply. Determine (a) the current flowing in the bulb
    and (b) the resistance of the bulb.
    [(a) 0.25 A (b) 960 ohm]
    6 - Graphs of current against voltage for two resistors P and Q are shown in Figure 2.6. Determine the value
    of each resistor.
    [2 m, 5 m]
    7 - Determine the p.d. which must be applied to a 5 k ohm resistor such Figure 2.6 that a current of 6 mA
    may flow.
    [30 V]

    Power and energy


    8 - The hot resistance of a 250 V filament lamp is 625 ohm . Determine the current taken by the lamp and
    its power rating.
    [0.4 A, 100 W]
    9 - Determine the resistance of a coil connected to a 150 V supply when a current of (a) 75 mA (b) 300 A
    flows through it.
    [(a) 2 k ohm (b) 0.5 M ohm]
    10 - Determine the resistance of an electric fire which takes a current of 12 A from a 240 V supply. Find
    also the power rating of the fire and the energy used in 20 h.
    [20 ohm , 2.88 kW, 57.6 kWh]
    11 - Determine the power dissipated when a current of 10 mA flows through an appliance having a
    resistance of 8 k ohm.
    [0.8 W]
    12 - 85.5 J of energy are converted into heat in nine seconds. What power is dissipated?
    [9.5 W]
    13 - A current of 4 A flows through a conductor and 10 W is dissipated. What p.d. exists across the ends of
    the conductor?
    [2.5 V]
    14 - Find the power dissipated when:
    (a) a current of 5 mA flows through a resistance of 20 k ohm .
    (b) a voltage of 400 V is applied across a 120 k ohm resistor .
    (c) a voltage applied to a resistor is 10 kV and the current flow is 4 mA.
    [(a) 0.5 W (b) 113 W (c) 40 W]
    15 - A battery of e.m.f. 15 V supplies a current of 2 A for 5 min. How much energy is supplied in this time?
    [9
    kJ]
    16 - In a household during a particular week three 2 kW fires are used on average 25 h each and eight 100
    W light bulbs are used on average 35 h each. Determine the cost of electricity for the week if 1 unit of
    electricity costs 7p.
    [12.46]

    17 - Calculate the power dissipated by the element of an electric fire of resistance 30 ohm when a current
    of 10 A flows in it. If the fire is on for 30 hours in a week determine the energy used. Determine also the
    weekly cost of energy if electricity costs 7.2p per unit.
    [3 kW, 90 kWh, 6.48]

    Fuses
    18 - A television set having a power rating of 120 W and electric lawnmower of power rating 1 kW are both
    connected to a 240 V supply. If 3 A, 5 A and 10 A fuses are available state which is the most appropriate for
    each appliance.
    [3 A, 5 A]

    With my best wishes

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