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With the help of a labelled circuit diagram illustrating the pattern of field lines of the magnetic field around a current-carrying straight long conducting wire. How is the right-hand thumb rule useful to find the direction of the magnetic field associated with a current-carrying conductor?

Right-hand thumb rule states that if a current-carrying straight conductor is held in the right hand with the thumb pointing... View Article

Why does a magnetic compass needle pointing North and South in the absence of a nearby magnet get deflected when a bar magnet or a current-carrying loop is brought near it. Describe some salient features of magnetic lines of field concept.

Current carrying loops act as bar magnets which have associated lines of the field. This changes the existing earth’s magnetic... View Article

What is the role of fuse, used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with a larger rating?

Fuse is used for protecting appliances due to short-circuiting or overloading. The fuse is rated for a certain maximum current... View Article

What is the difference between a direct current and an alternating current? How many times does AC used in India change direction in one second?

b) 100 times Explanation Direct current always flows in one direction but the alternating current reverses its direction periodically. The... View Article

What is the role of the two conducting stationary brushes in a simple electric motor?

c) Both Explanation The two conducting stationary brushes draw current from the battery and supply it to the armature of... View Article

Name four appliances wherein an electric motor, a rotating device that converts electrical energy to mechanical energy, is used as an important component. In what respect motors are different from generators?

Vacuum cleaners,Washing Machines, Air conditioners, Grinders and mixers are a few home appliances that use electric motors. The difference between... View Article

What does the divergence of magnetic field lines near the ends of a current-carrying straight solenoid indicate?

When a current passes through it, it creates a nearly uniform magnetic field inside or along the axis of the... View Article

Meena draws magnetic field lines of the field close to the axis of a current-carrying circular loop. As she moves away from the centre of the circular loop she observes that the lines keep on diverging. How will you explain her observation?

With a decrease in the distance strength of the magnetic field decreases. The decrease in degree of closeness of the... View Article

What does the direction of thumb indicate in the right-hand thumb rule? In what way this rule is different from Fleming’s left-hand rule?

Thumb held by curled fingers indicates the direction of current in right hand rule whereas in fleming’s left hand rule... View Article

It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving (i) alpha particles, (ii) neutrons? Justify your answer.

(i) Yes (ii) No. Alpha particles are positively charged particles and therefore a thin beam of moving alpha particles constitutes... View Article

A magnetic compass shows a deflection when placed near a current-carrying wire. How will the deflection of the compass get affected if the current in the wire is increased? Support your answer with a reason.

It the current is increased in the conductor the deflection of the compass needle increases. This is because the strength... View Article

AB is a current-carrying conductor in the plane of the paper as shown in the figure. What are the directions of magnetic fields produced by it at points P and Q? Given r1 > r2, where will the strength of the magnetic field be larger?

By applying the right-hand thumb rule, the direction of magnetic field would be anti-clockwise as shown in diagram around the direction... View Article

Under what conditions permanent electromagnet is obtained if a current-carrying solenoid is used? Support your answer with the help of a labelled circuit diagram.

Closed-circuit Core of soft iron When a ferromagnetic material rod is permanently placed inside the solenoid, the metal greatly increases... View Article

A magnetic compass needle is placed in the plane of paper near point A. In which plane should a straight current-carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?

In the plane of the paper itself. The axis of the compass is vertical and the field due to the... View Article

The most important safety method used for protecting home appliances from short-circuiting or overloading is (a) earthing (b) use of fuse (c) use of stabilizers (d) use of electric meter

b) use of fuse Explanation The primary use of an electric fuse is to protect electrical equipment from excessive current... View Article

To convert an AC generator into DC generator (a) split-ring type commutator must be used (b) slip rings and brushes must be used (c) a stronger magnetic field has to be used (d) a rectangular wire loop has to be used

a) split-ring type commutator must be used Explanation A split-ring commutator makes the current change direction every alternate half-rotation, whereas... View Article

The strength of the magnetic field inside a long current carrying straight solenoid is (a) more at the ends than at the centre (b) minimum in the middle (c) same at all points (d) found to increase from one end to the other

(c) same at all points Explanation Inside the solenoid magnetic field lines are straight. This indicates strong magnetic field. Hence,... View Article

A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in Figure. The direction of the magnetic field at a point will be North to South (a) directly above the wire (b) directly below the wire (c) at a point located in the plane of the paper, on the north side of the wire (d) at a point located in the plane of the paper, on the south side of the wire

b) directly below the wire Explanation The Fleming’s right-hand rule shows the direction of induced current when a conductor moves... View Article

Choose the incorrect statement (a) Fleming’s right-hand rule is a simple rule to know the direction of induced current (b) The right-hand thumb rule is used to find the direction of magnetic fields due to current-carrying conductors (c) The difference between the direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically (d) In India, the AC changes direction after every 1/50 second

d) In India the AC changes direction after every 1/50 second Explanation Fleming’s right-hand rule shows the direction of induced... View Article

In the arrangement shown in the figure there are two coils wound on a non-conducting cylindrical rod. Initially, the key is not inserted. Then the key is inserted and later removed. Then (a) the deflection in the galvanometer remains zero throughout (b) there is a momentary deflection in the galvanometer but it dies out shortly and there is no effect when the key is removed (c) there are momentary galvanometer deflections that die out shortly; the deflections are in the same direction (d) there are momentary galvanometer deflections that die out shortly; the deflections are in opposite directions

d) there are momentary galvanometer deflections that die out shortly, the deflections are in opposite directions Explanation In the figure, two... View Article

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