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Electricity-Important Questions & Preparation Tips

Jul 20, 2013 16:21 IST

    In this article you will get the clue that from where and how the questions are being framed from the chapter Electricity.The experts of jagranjosh.com have full confidence that you will not miss any of the questions in the board exam as well as in competitive exams from this chapter if you will keep the following terms / question in your mind while studying

    Go through the some questions given here as example and get an idea that how questions can be framed

    • What do you mean by static electricity and current electricity?
    • SI unit of electric charge and current
    • Basic differences between conductor and insulator
    • What are free electrons?
    • Electric potential in words and formula along with potential energy and its SI unit
    • How much work is done in moving a charge of 2 coulombs from a point at 118 volts to a point at 128 volts?
    • Device used to measure p.d?
    • Relation between potential difference, work done, and charge moved?
    • The atoms of copper contain electrons and the atoms of rubber also contain electrons? Why does copper conducts electricity?
    • What is Ammeter? And why should it have low resistance? Explain with diagram
    • An electric bulb draws a current of 0.25 A for 20 minutes. Calculate the amount of electric charge that flows through the circuit
    • Process of flowing current in a wire
    • Electric circuit and different symbols of electric components?
    • Potential difference between two points of a wire carrying 2 ampere current is 0.1 volt. Calculate the resistance between these points.
    • Distinguish between good conductor, resistors and insulators. Give example.
    • Why do electricians wear gloves while working with electricity?
    • What is resistivity of a substance? And on what factors a resistivity of a substance depends?
    • A copper wire of length 2m and area of cross- section 1.7 x 10-6  m2 has a resistance of 2 x 10-2 ohms. Calculate the resistivity of copper.
    • Write down an expression for the resistance of a metallic wire in terms of the resistivity?
    • Ohm’s law and it’s application
    • Resistivity of a conductor depends on
    • A resistance of 6 ohms is connected in series with another resistance of 4 ohms. A potential difference of 20 volts is applied across the combination. Calculate the current through the circuit and potential difference across the 6 ohm resistance.
    • What is meant by the “series combination” and “parallel combination” of resistances? In which case the resultant resistance is:

               i. Less
               ii. More than either of the individual resistances?

    • An electric bulb of resistance 20 ohms and a resistance wire of 4 ohms are connected in series with a 6 V battery. Draw the circuit diagram and calculate:

               a. Total resistance of the circuit
               b. Current through the circuit
               c. Potential difference across the electric bulb
               d. Potential difference across the resistance wire

    • Disadvantage of series circuits for domestic wiring
    • Advantages of parallel circuit in domestic wiring
    • Why lights are in house wired in series
    • How to calculate electric power
    • What is the relation between kilowatt-hour and joule?
    • What do you understand by watt? Write down an equation linking watts, volts, amperes
    • Heating effect of current and different formula to calculate the heat energy
    • Joules law of heating
    • All appliances which run on electricity do not convert all the electric energy into heat. Explain
    • Factors on which the heat produced by an electric current depends?  
    • Why is argon or nitrogen filled in electric bulb instead of air?
    • SI unit of

               I. Electric charge
               II. Potential difference
               III. Electric current
               IV. Resistance
               V. Power
               VI. Electric energy

    Q1 .When batteries are places in a flashlight, the positive terminal of one is connected to the negative terminal of the next. Why?
    a. So electricity can flow from the battery to the flashlight to a complete circuit.
    b. So the current is slowed as it enters the next battery
    c. So the voltage is increased as it enters the next battery
    d. So electromagnetic interference is reduced

    Q2. A parallel plate capacitor contains a positively charged plate on the left, and a negatively charged plate on the right. An electron in between the plates is moved to the right. Which statement is true?
    a. The potential energy of the electron is increasing and it is moving to a region having a lower potential.
    b. The potential energy of the electron is increasing and it is moving to a region having a higher potential.
    c. The potential energy of the electron is decreasing and it is moving to a region having a lower potential.
    d. The potential energy of the electron is decreasing and it is moving to a region having a higher potential

    Q3. Which of the following property of a proton can change while it moves freely in a magnetic field? (there may be more than one correct answer)
    a. Mass
    b. Speed
    c. Velocity
    d. Momentum

    Q4. Two bulbs marked 200 watt-250 volts and 100 watt-250 volts are joined in series to 250 volts supply. Power consumed in circuit is
    a. 33 watt
    b. 67 watt
    c. 100 watt
    d. 300 watt.

    Q5. The resistance of a wire of iron is 10 ohm and temperature coefficient of resistivity is 5 x 10-3/ºC. At 20 ºC it carries 30 milli ampere of current. Keeping constant potential difference between its ends, the temperature of the wire is raised to 120 ºC. The current in milli amperes that flows in the wire is:
    a. 20
    b. 15
    c. 10
    d. 40

    Q6. The electric field 2.8 cm from a small object points towards the object points towards the object with strength of 180,000N/C. what is the object’s charge
    a. +17nC
    b. -16nC
    c. -17nC
    d. +16nC

    Q7. When a current 'I' flows through a resistance 'R' for time 't' the electrical energy spent is given by
    a. I R t
    b. I2 R t
    c. I R2 t
    d. I 2 R/t

    Q8. The value of the following is given by 100 (kilo ampere ) x ( micro ampere ) 100 milli ampere * 10 ampere
    a. 0.001 A
    b. 0.1 A
    c. 1 A
    d. 10A.

    Q9.Which of the following statement is not true, regarding the electrical set-up for the verification of Ohm’s law:
    a. The voltmeter is connected in parallel with the known resistance
    b. The ammeter is connected in series circuit
    c. The rheostat can only increase the resistance in electric circuit
    d. The single key is used to switch on/off the electric circuit

    Q10. Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in them are in the ratio.
    a. 1:2
    b. 2:1
    c. 4:1
    d. 1:1

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