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XAVIER’S POINT OF EDUCATION, CLASS:- X, , Sub:- Physics, , Chapter (Electricity), , (By-Vivek Sir), , DPS-1, Topic-Charge,Electric current and Electric potential/voltage, Multiple choice type questions, 1. C is the charge contained in, (I) 1.6 × 1019 electrons (II) 1.6 × 1018 electrons (III) 6.25 × 1019 electrons (IV) 6.25 × 1018 electrons, 2. The device used to measure potential difference is called, (I) galvanometer, (II) ammeter, (III) potentiometer (IV) voltmeter, 3. The unit for measuring electric charge is, (I) ampere, (II) volt, (III) coulomb/second (IV) coulomb, 4. The work done in taking a unit charge from one point to another in an electric circuit is a measure of, (I) potential difference (II) potential, (III) current, (IV) power, 5. Potential difference is also known as, (I) potential energy, (II) wattage, (III) ampereage, (IV) voltage, 6. The SI unit of electric current is, (I) coulomb, (II) volt, (III) ampere, (IV) joule, 7. Statement I : An ammeter is connected in parallel in a circuit., Statement II : A voltmeter is connected in series in a circuit., Statement III : An ammeter has a very low resistance., Statement IV : A voltmeter has a very high resistance., (I) I, II, (II) I, IV, (III) II, III, (IV) none of these, 8. The potential at a pint is 12 V. The work done in bringing a 2.5 C charge from infinity to this point will, be, (I) 12 J, (II) 25 J, (III) 30 J, (IV) 4.8 J, 9. Joule/coulomb is equivalent to, (I) ampere, (II) watt, (III) ohm, (IV) volt, 10. Which of the following has no ‘+’ or ‘-‘, (I) resistor, (II) ammeter, (III) cell, (IV) voltmeter, 11. A charge is moved from point P to point Q. The work done per unit charge in this process is, (I) the current from P to Q, (II) the potential difference between Q and P, (III) the potential at P, (IV) the potential at Q, 12. The free electrons of a metal, (I) are free to move anywhere in the metal, (II) move only on the surface of the metal, (III) are free to escape from the surface of the metal (IV) are free to fall into the nuclei, 13. In a metal,, (I) all electrons are bound to their parent atoms (II) all electrons are free to move, (III) some electrons are free to move, (IV) none of these, 14. Statement I : In a parallel connection, the potential difference across each element is the same., Statement II : In a series connection, the same current flows through each element, Which of the above statements is (are) correct?

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(I) only I, (II) only II, (III) Both I and II, (IV) None, 15. When a negative charge is released from a point P, it moves along a line PQ. If the potential at P is 25 V,, and it varies uniformly along PQ, the potential at Q, (I) may be 30 V, (II) may be 25 V, (III) must be 25 V, (IV) may be 20 V, , Very short answer type questions, 1., 2., 3., 4., 5., 6., 7., , Write the unit of electric charge., Define electric potential., Define potential difference between two points., What is the unit of electric potential and potential difference?, If the electric potential at any point is 1 volt, what does it mean?, How is a constant potential difference across the ends of a conducting wire maintained?, Calculate the work done in moving a charge of 3 C across two points having potential difference of 12, V., 8. Four cells of 2.5 V each are connected in series and used as a battery. What is the potential difference, across the terminals of the battery?, 9. A dry cell is flat at one end and has a small cap at the other end. Which end is at a lower potential?, 10. How is the direction of electric current related to the direction of flow of electrons in a wire?, 11. Define electric current., 12. What is the SI unit of electric current?, 13. By what other name is the unit coulomb/second called?, 14. How many milliamperes are there in one ampere?, 15. Define the unit of current., 16. Define electric current., 17. What do the following symbols represent in circuit diagrams :, , 18. Which instrument is used to measure potential difference across a conductor?, 19. Name the device used to measure electric current., 20. How is a voltmeter connected in a circuit to measure the potential difference across two points?, 21. To measure current in an electric circuit, is the ammeter connected in series or parallel?, 22. Among copper, nichrome and ebonite, what would you use to make the handle of an electric iron?, 23. A charge of 3 C passes through a given point in 10 s. What is the current at that point?, 24. State the relation between work, charge and potential difference for an electric circuit ?, 25. What is an electric circuit ? Distinguish between an open and a closed circuit ?, 26. Silver is a better conductor of electricity than copper but conducting wires are often made of copper, and not silver. Explain why., , Short answer type questions, 1. Define electric charge. What are the two types of electric charges?, 2. Calculate the number of electrons on 2 C of charge., 3. What is the relation between charge moved, potential difference and work done ? Calculate the work, done in moving a charge of 3 C from a point at 24 V to a point at 12 V.

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4. What is the energy given to 4 C of charge passing through a 24 V battery ? Also calculate the work done, on the charge., 5. 100 J of work is dine in transferring 20 C of charge from one terminal of a cell to the other. What is the, potential difference across the terminals of the cell ?, 6. A current of 3 A flows for 10 s through a lamp across which the potential difference is 24 V. How much, electrical energy is converted into heat and light ? Compare it with the electrical energy converted to, heat and light in a lamp across which the potential difference is 24 V and through which a charge of 10, C passes., 7. A charge of 20 C leaves a cell in 10 s with 150 J of energy delivered to an external circuit. Calculate the, current that flows from the cell and the potential difference across the cell., 8. How many electrons should pass through a conductor in 1 s to give a current of 2 A ?, 9. Calculate the energy transferred per second to an electric iron when it is connected to the 220 V mains, supply. The current that flows through the iron is given to be 5 A., 10. What is the difference between a conductor and an insulator ? State two examples of each., 11. Explain why a voltmeter should have a very high resistance and why an ammeter should have a very, low resistance., 12. Draw the circuit symbols for the following :, (a) battery of four cells, (b) galvanometer, (c) variable resistance, (d) fixed resistance, (e) closed switch, (f) open switch, 13. What is meant by a circuit diagram ? Draw a labelled circuit diagram of an electric circuit having a, battery of two cells, a closed plug key, a resistor, a bulb, a voltmeter and an ammeter., 14. Why is an ammeter likely to burn out if you connect it in parallel ?, 15. A lightning flash carries a charge of 5 C that flows for 5 milliseconds. Calculate the current and the, energy if the voltage is 12 MV., , Long answer type questions, 1. Explain why conductors conduct electricity while insulators do not., 2. What is a voltmeter ? How is it connected in an electric circuit to measure the potential difference ?, Explain using a diagram., 3. What is an ammeter ? How is an ammeter connected in an electric circuit? Explain with the help of a, diagram., 4. Explain how we get a continuous flow of current in a metal wire connected to a cell., 5. An electric device is connected to a mains supply of 110 V causing a current of 4 A through the device. Calculate, the following :, (a) The charge flowing through the circuit per second., (b) The number of electrons passing through the circuit per second., (c) the amount of energy transferred to the device per second., 6. (a) What is meant by electric potential ? State its unit., (b) What is meant by saying that the potential at a point is 1 V ?, (c) If a charge of 10 millicoulombs is moved from infinity to a point at which the electric potential is 12 V, how, much work is done in the process ?, (d) Calculate the work done in bringing a particle with a charge of 2.5 coulombs from a point at a potential of 60, V to a point at a potential of 120 V., (e) Which instrument do we use to measure the potential difference between two points in an electric circuit ?, Does it have a very high or very low resistance ? Give reason for your answer.

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7. (a) How is current in a circuit measured ?, (b) A charge of 30 C passes through a wire in 20 seconds. Calculate the current in the wire., (c) Explain the calculated value of current in (b) in terms of number of electrons flowing in the wire., (d) If the potential difference across the wire in (b) is 220 V, how much work is done in moving the 30 C charge?, 8. What do the following symbols represent in a circuit? Write the name and one function of each., , Hots, 1. With the help of an example, explain how a positively charged body is at a higher potential than a negatively, charged one., 2. What will happen if you connect an ammeter in parallel in an electric circuit., 3. What will happen if your connect a voltmeter in series in an electric circuit ?, 4. A glass rod rubbed with a silk cloth is brought close to a thin stream of water coming out of a tap. What will you, observe ? Explain your answer., 5. Atoms of both copper and rubber have electrons. Then why does copper conduct electricity while rubber does, not?, 6. A student, Vagisha set-up an electric circuit as shown in the figure to measure the current in the circuit and the, potential difference across lamp, 𝐿1 ., (a) State if the lamps 𝐿1 and 𝐿2 are in parallel or in series., (b) What is(are) the mistake(s), if any, that Vagisha has made in setting up the circuit?, (c) Correct the mistake(s), if any, that Vagisha has made and draw the correct circuit diagram.