1) What is an electromagnet?
i) Draw a circuit diagram to show how a soft iron piece an be transformed into an electromagnet.
ii) How can we determine north and south pole of an electromagnet with the help of magnetized iron bar?
2) How will the magnetic field produced in a current carrying a circular coil change, if we increase the:
(i) Value of current flowing through it?
(ii) Distance of point P from the coil?
(iii) Number of turns of the coil?
3) With the help of a diagram for experimental set up, describe an activity to demonstrate that the strength of a magnetic field at a point increases with increase in current in the straight conductor.
4) (a) Name two electrical appliances of daily use in which electric motor is used.
(b) Name and state the principle on which an electric motor works.
5) In Faraday’s experiment if instead of moving the magnet towards the coil we move the coil towards the magnet, will there be any induced current? Justify your answer. Compare the two cases.
6) Define electromagnetic induction.
i) On what factors does the value of induced current produced in a circuit depend?
ii) Name and state the rule used for determination of direction of induced current.
7) State Fleming’s right hand rule.
8) List two characteristics of the material to be used in fuse wire. Name the material it is made up of. A fuse is always connected in series in an electric circuit. Justify this statement giving reason.
9) Series arrangements are not used for domestic circuits. List any three reasons.
10) (a) What is the role of fuse used in series with any electrical appliance?
(b) Why should a fuse with defined rating not be replaced by one with a larger rating?
(c) Name the three types of wires used in household circuits. Out of these three which wire is used as a safety measure especially for those appliances that have metallic body? State the colour of insulation used for this wire. How it ensures the safety of the user?(
11) List four characteristics features of circuit used in residential building.
12) State the significance of the following devices in domestic circuits:
(i) Main switch
(ii) Mains fuse
(iii) Electricity meter
i) What are magnetic field lines? How is the direction of a magnetic field at a point determined? Mention two important properties of magnetic field lines.
ii) Draw the magnetic field lines (incliuding field directions) of the magnetic field due to a circular coil of current. Name any two factors on which the magnitude of the magnetic field due to this coil depends.
14) How will the magnetic field produced in a current carrying circular coil change if we
(i) Increase the value of current.
(ii) Increase the distance from the coil.
(iii) Increase the number of turns of the coil?
15) Draw the magnetic field lines (Including field directions) of the magnetic field due to a long straight solenoid. Name any two factors on which the magnitude of the magnetic field due to this solenoid depends.
16) State the rule to determine the direction of force experienced by a current carrying conductor in a magnetic field. How will this force get affected on:
(i) double the magnitude of current?
(ii) Reserving the direction of current flow?
17) Draw an appropriate schematic diagram showing common domestic circuits and discuss the importance of fuse. Why is it that burnt out fuse should be replaced by another fuse of identical rating?
18) (a)Write four properties (characteristics) of magnetic lines of forces.
(b) Give two uses of magnetic compass.
19) (a) What is a solenoid? Draw the pattern of magnetic field lines around a current carrying solenoid.
(b) What is the pattern of field lines inside a solenoid? What do they indicate?
(c) How is the magnetic field produced in a solenoid used?
d) How can this field be utilized to magnetise a piece of soft iron?
20) You are given three identical looking bars one of which is a magnet, the other made of a magnetic material and the third made of the third made of a non – magnetic material. Using just three bars how will you find out which is which?
21) How can we demonstrate the formation of magnetic field surrounding a magnet?
22) Why do two magnetic field lines never intersect each other? Explain.
23) Briefly explain an activity to plot the magnetic field lines produced round a straight current carrying conductor.
24) How is the fuse connected in an electric circuit?
25) A current through a horizontal power line flows in east to west direction. What is the direction of magnetic field at a point directly below it and at a point directly above it? Name the rule you have applied in this case.
26) Compare the pattern of the field produced in case of a current carrying solenoid with the magnetic field of a bar magnet.
27) With the help of diagram describe an experiment to show that a change in current flowing through a coil induces an electric current in a neighboring coil.
28) An electric fuse of rating 3 A is connected in a circuit in which an electric iron of power 1.5 kilo watt is connected which operates at20 V. What would happen? Explain.
29) An electric oven is 1.5 kW is operated in a domestic circuit (220 V) that has a current rating of 5 A. What result do you expect in this case? Explain.
30) Name the three factors on which the force on the current carrying conductor depend?