Page |1
CHAPTER - 1
EFFECTS OF ELECTRIC CURRENT
1. Find the relation between the terms in the first pair and complete the second pair. Incandescent lamp
: Tungsten
Heating coil of heating appliances : ……………..
2. (a) Which among the following is not a discharge lamp?
(Sodium vapour lamp, Arc lamp, Fluorescent lamp, LED lamp)
(b) Explain the working of discharge lamp.
3. An incandescent lamp bears the marking 200 V, 100 W.
(a) What does 100 W indicate?
(b) What is the resistance of its filament?
(c) Write an advantage of LED lamp over incan- descent lamp.
4. Write the energy change taking place in the given devices.
(1) Incandescent Lamp (ii) Electric Mixie
5. (a) Name the part of a heating equipment in which the electric energy is converted into heat energy.
(b) Name the substance used to make this part
6. 2A current flows through an electric heating device connected to 230 V supply.
(a) The quantity of charge that flows through the circuit in 5 minutes is:
(b) What is the resistance of the device?
(c) Calculate the power of the heating device.
7. Three resistances of 4 £2, 62 and 12 2 are given to you.
(a) What is the highest resistance that you can get using all of them?
(b) What is the lowest resistance that can be obtained by using the 6 2 and 12 2 resistances?
8. Specification of two electrical heaters are given below:
a) Which heater require a fuse of higher amperage?
b) Which of the heaters generate more heat when they work for 5 minutes under the same voltage rating?
Explain the reason.
9. Correct the following statements by modifying the underlined words appropriately if it is wrong.
a) Heating coils are made up of materials having high resistivity and low melting point.
b) In the incandescent lamps, vaporization of filaments can be reduced by using hydrogen or nitrogen at low
pressure.
JAMSHID AHAMMED
, Page |2
10. If intensity of electric current in a circuit is doubled, the heat energy developed in this circuit
increases……………times
11. Which of the following light source does not contain mercury in it?
(fluorescent lamp, LED, CFL)
12. Write any two characteristic properties of the material used as heating coil in heating devices.
13. Explain how light energy is produced in discharge lamps?
14.(a) Which material is used as filament in incandescent lamps?
(b) What are the characteristic properties of the material used as filament?
(c) Why these lamps are filled with nitrogen?
15. Usually we connect resistors in series and parallel.
(a) In which type of connection does the resultant resistance of the circuit decreases?
(b) Two resistors of 1000 are connected in series with a 250 V supply. Calculate the heat ener-gy produced
when current flows through it for 2 seconds.
(c) State whether the quantity of heat, produced increases or decreases, if these resistors connected in
parallel in the same circuit with 250 V supply. Justify your answer.
16. Write the electrical devices which converts electrical energy to mechanical energy.
Electric Iron
Loud speaker
Soldering Iron
Electric Mixie
17. Nichrome wires are used as heating coil. Write any two reasons for the same.
18. Why does a heater having low resistant heating coil gets heated more? Explain.
19. The heat generated in a current carrying conductor can be explained by a famous law.
(a) Write the name of this law.
(b) Write the mathematical equation for this law. Explain each letters used in the equation.
20. Identify the relationship in the first pair and complete the second one.
Storage battery (While charging) - Chemical effect
- Heating effect
22. Suppose you have to replace an incandescent lamp at your house. Following lamps are available
Incandescent lamp, CFL, LED, Fluorescent lamp Which of these lamp would you select? Justify your
selection.
23. Analyse the figure and answer the following
a) If the switch S1 is on, which bulb will glow? How much current is flowing through the fuse at this time?
b) If both the switches are on, what changes can be observed in the circuit? Justify your answer.
CHAPTER - 2
MAGNETIC EFFECT OF ELECTRIC CURRENT
JAMSHID AHAMMED
, Page |3
1. Observe the figure of a moving coil loudspeaker.
(a) Name the parts labelled as A and B.
(b) Write the function of diaphragm in this device.
2. Write any two methods to increase the magnetic strength of a current carrying solenoid.
3. DC current is flowing through a solenoid AB. The direction of current at the end A is anticlockwise.
(a) Write the polarity at the end A.
(b) The solenoid is replaced by a current carrying conductor. Give the name of the law that helps to
determine the direction of magnetic field produced.
4. The magnetic field around a current carrying conductor AB is
given in the figure. Based on Maxwell's right hand screw rule, find the
direction of the current through the conductor.
5. Observe the figure of a DC motor.
a. Write the name of the parts labelled as A and B.
b. What are the changes to be made so as to convert
this device into an AC generator?
6. Name the arrangement in a DC motor to sustain the rotation of the armature in one direction.
7. Solenoids are used to make electromagnets.
(a) If the direction of the DC current through the solenoid at the end facing us is in clockwise, which
magnetic pole is developed at this end?
(b) Suggest two methods to increase the magnetic field strengths of a solenoid.
8. From the following choose the instrument that works on motor principle.
(AC - Generator, Moving Coil Microphone, DC-Generator, Moving Coil Loud Speaker)
9. Identify the magnetic pole at the end of a solenoid at which current is in the clockwise direction.
10. Correct the following statement by changing the underlined words.
The direction of deflection of magnetic nee- dle placed near a current carrying conductor depends on the
intensity of electric current through that conductor.
11. Explain the working of split ring commutator in a DC motor.
12. a) Write any two important parts of a moving coil loud speaker.
b) Write the working principle of this device
CHAPTER - 3
ELECTROMAGNETIC INDUCTION
1. Secondary coil of a transformer has double turns in the Secondary ? than that of its primary coil . If the
voltage applied in the primary coil is 25 V , what will be the voltage in the secondary?
( 25 V , 50 V , 2 V , 12.5 V )
JAMSHID AHAMMED
, Page |4
2. Which arrangement converts the AC induced in the armature of DC generator into DC ?
3. Some characteristics of step up transformers and step down transformers are given below. Select the
statements suitable for step up transformers.
(a ) Primary voltage is greater than secondary voltage .
(b) Secondary voltage is greater than primary voltage
(c) Current in the primary coil is greater than that in the secondary coil
(d) Current in the secondary coil is greater than that in the primary coil.
(e) Thick wires are used in the primary.
(f) Thick wires are used in the secondary.
4 . The non - rotating part in a dc motor is : ( Armature , Split ring , Graphite Brush )
5. Write any two relevant first aids to be given in the case of electric shock .
6. Explain the following .
( a ) Electromagnetic induction
( b ) Induced emf .
7. The voltage of electric power generated is increased from 11 kV to 220 kV in power trans mission . But
the household supply is provided at 230 V.
( a ) Write the type of transformer used at the first phase of power transmission .
( b ) Write the type of transformer used at the distribution line .
( c ) Write any two structural differences between step up and step down transformer
8. Observe the figure .
( a ) Identify the Generator .
( b ) Write the working principle of the generator .
( c ) Which type of emf is induced in the armature ?
( d ) Write the function of split ring commutator used in this generator
9. The graphical representation of emf obtained from three electrical sources are given below
( a ) Identify any two sources .
( b ) Write any two peculiarities of each of the emf
Shown in the graph ( A ) and ( B ) .
10. Two stages of experiment conducted with a solenoid and a magnet is given below .
( Magnets shown in fig . A and fig . B are station ary magnet and a
moving magnet respectively) .
(a) In which stage , the galvanometer deflects ?
(b) Explain the reason for this deflection in galvanometer with the
help of scientific principle that you have learned
(c) Write any two devices that works on this principle .
11. What is the use of watt hour meter in a house hold circuit?
12. In household electrical appliances three pin plugs are used to ensure safety .
a ) How is earth pin different from the other pins ?
b ) Which part of the equipment is connected to the earth line ?
13. Which among the following is the graphical representation of the output emf in a DC generator ?
JAMSHID AHAMMED
CHAPTER - 1
EFFECTS OF ELECTRIC CURRENT
1. Find the relation between the terms in the first pair and complete the second pair. Incandescent lamp
: Tungsten
Heating coil of heating appliances : ……………..
2. (a) Which among the following is not a discharge lamp?
(Sodium vapour lamp, Arc lamp, Fluorescent lamp, LED lamp)
(b) Explain the working of discharge lamp.
3. An incandescent lamp bears the marking 200 V, 100 W.
(a) What does 100 W indicate?
(b) What is the resistance of its filament?
(c) Write an advantage of LED lamp over incan- descent lamp.
4. Write the energy change taking place in the given devices.
(1) Incandescent Lamp (ii) Electric Mixie
5. (a) Name the part of a heating equipment in which the electric energy is converted into heat energy.
(b) Name the substance used to make this part
6. 2A current flows through an electric heating device connected to 230 V supply.
(a) The quantity of charge that flows through the circuit in 5 minutes is:
(b) What is the resistance of the device?
(c) Calculate the power of the heating device.
7. Three resistances of 4 £2, 62 and 12 2 are given to you.
(a) What is the highest resistance that you can get using all of them?
(b) What is the lowest resistance that can be obtained by using the 6 2 and 12 2 resistances?
8. Specification of two electrical heaters are given below:
a) Which heater require a fuse of higher amperage?
b) Which of the heaters generate more heat when they work for 5 minutes under the same voltage rating?
Explain the reason.
9. Correct the following statements by modifying the underlined words appropriately if it is wrong.
a) Heating coils are made up of materials having high resistivity and low melting point.
b) In the incandescent lamps, vaporization of filaments can be reduced by using hydrogen or nitrogen at low
pressure.
JAMSHID AHAMMED
, Page |2
10. If intensity of electric current in a circuit is doubled, the heat energy developed in this circuit
increases……………times
11. Which of the following light source does not contain mercury in it?
(fluorescent lamp, LED, CFL)
12. Write any two characteristic properties of the material used as heating coil in heating devices.
13. Explain how light energy is produced in discharge lamps?
14.(a) Which material is used as filament in incandescent lamps?
(b) What are the characteristic properties of the material used as filament?
(c) Why these lamps are filled with nitrogen?
15. Usually we connect resistors in series and parallel.
(a) In which type of connection does the resultant resistance of the circuit decreases?
(b) Two resistors of 1000 are connected in series with a 250 V supply. Calculate the heat ener-gy produced
when current flows through it for 2 seconds.
(c) State whether the quantity of heat, produced increases or decreases, if these resistors connected in
parallel in the same circuit with 250 V supply. Justify your answer.
16. Write the electrical devices which converts electrical energy to mechanical energy.
Electric Iron
Loud speaker
Soldering Iron
Electric Mixie
17. Nichrome wires are used as heating coil. Write any two reasons for the same.
18. Why does a heater having low resistant heating coil gets heated more? Explain.
19. The heat generated in a current carrying conductor can be explained by a famous law.
(a) Write the name of this law.
(b) Write the mathematical equation for this law. Explain each letters used in the equation.
20. Identify the relationship in the first pair and complete the second one.
Storage battery (While charging) - Chemical effect
- Heating effect
22. Suppose you have to replace an incandescent lamp at your house. Following lamps are available
Incandescent lamp, CFL, LED, Fluorescent lamp Which of these lamp would you select? Justify your
selection.
23. Analyse the figure and answer the following
a) If the switch S1 is on, which bulb will glow? How much current is flowing through the fuse at this time?
b) If both the switches are on, what changes can be observed in the circuit? Justify your answer.
CHAPTER - 2
MAGNETIC EFFECT OF ELECTRIC CURRENT
JAMSHID AHAMMED
, Page |3
1. Observe the figure of a moving coil loudspeaker.
(a) Name the parts labelled as A and B.
(b) Write the function of diaphragm in this device.
2. Write any two methods to increase the magnetic strength of a current carrying solenoid.
3. DC current is flowing through a solenoid AB. The direction of current at the end A is anticlockwise.
(a) Write the polarity at the end A.
(b) The solenoid is replaced by a current carrying conductor. Give the name of the law that helps to
determine the direction of magnetic field produced.
4. The magnetic field around a current carrying conductor AB is
given in the figure. Based on Maxwell's right hand screw rule, find the
direction of the current through the conductor.
5. Observe the figure of a DC motor.
a. Write the name of the parts labelled as A and B.
b. What are the changes to be made so as to convert
this device into an AC generator?
6. Name the arrangement in a DC motor to sustain the rotation of the armature in one direction.
7. Solenoids are used to make electromagnets.
(a) If the direction of the DC current through the solenoid at the end facing us is in clockwise, which
magnetic pole is developed at this end?
(b) Suggest two methods to increase the magnetic field strengths of a solenoid.
8. From the following choose the instrument that works on motor principle.
(AC - Generator, Moving Coil Microphone, DC-Generator, Moving Coil Loud Speaker)
9. Identify the magnetic pole at the end of a solenoid at which current is in the clockwise direction.
10. Correct the following statement by changing the underlined words.
The direction of deflection of magnetic nee- dle placed near a current carrying conductor depends on the
intensity of electric current through that conductor.
11. Explain the working of split ring commutator in a DC motor.
12. a) Write any two important parts of a moving coil loud speaker.
b) Write the working principle of this device
CHAPTER - 3
ELECTROMAGNETIC INDUCTION
1. Secondary coil of a transformer has double turns in the Secondary ? than that of its primary coil . If the
voltage applied in the primary coil is 25 V , what will be the voltage in the secondary?
( 25 V , 50 V , 2 V , 12.5 V )
JAMSHID AHAMMED
, Page |4
2. Which arrangement converts the AC induced in the armature of DC generator into DC ?
3. Some characteristics of step up transformers and step down transformers are given below. Select the
statements suitable for step up transformers.
(a ) Primary voltage is greater than secondary voltage .
(b) Secondary voltage is greater than primary voltage
(c) Current in the primary coil is greater than that in the secondary coil
(d) Current in the secondary coil is greater than that in the primary coil.
(e) Thick wires are used in the primary.
(f) Thick wires are used in the secondary.
4 . The non - rotating part in a dc motor is : ( Armature , Split ring , Graphite Brush )
5. Write any two relevant first aids to be given in the case of electric shock .
6. Explain the following .
( a ) Electromagnetic induction
( b ) Induced emf .
7. The voltage of electric power generated is increased from 11 kV to 220 kV in power trans mission . But
the household supply is provided at 230 V.
( a ) Write the type of transformer used at the first phase of power transmission .
( b ) Write the type of transformer used at the distribution line .
( c ) Write any two structural differences between step up and step down transformer
8. Observe the figure .
( a ) Identify the Generator .
( b ) Write the working principle of the generator .
( c ) Which type of emf is induced in the armature ?
( d ) Write the function of split ring commutator used in this generator
9. The graphical representation of emf obtained from three electrical sources are given below
( a ) Identify any two sources .
( b ) Write any two peculiarities of each of the emf
Shown in the graph ( A ) and ( B ) .
10. Two stages of experiment conducted with a solenoid and a magnet is given below .
( Magnets shown in fig . A and fig . B are station ary magnet and a
moving magnet respectively) .
(a) In which stage , the galvanometer deflects ?
(b) Explain the reason for this deflection in galvanometer with the
help of scientific principle that you have learned
(c) Write any two devices that works on this principle .
11. What is the use of watt hour meter in a house hold circuit?
12. In household electrical appliances three pin plugs are used to ensure safety .
a ) How is earth pin different from the other pins ?
b ) Which part of the equipment is connected to the earth line ?
13. Which among the following is the graphical representation of the output emf in a DC generator ?
JAMSHID AHAMMED
