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Given below are names of some animals. (i) Goat (ii) Human beings (iii) Cockroach (iv) Eagle which of the above animals form a pair of omnivores? (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (ii) and (iv)

(b) (ii) and (iii) Both human beings and cockroaches are omnivores as the feed upon plants or plant products as well on other organisms. Goat... View Article

Draw an appropriate schematic diagram showing common domestic circuits and discuss the importance of fuse. Why is it that a burnt-out fuse should be replaced by another fuse of identical rating?

A fuse in a circuit prevents damage to the appliances and the circuit due to overloading. Fuse of a particular rating is used with a particular... View Article

Describe the working of an AC generator with the help of a labelled circuit diagram. What changes must be made in the arrangement to convert it to a DC generator?

Faraday’s law electromagnetic induction states that whenever a conductor moves in a magnetic field EMF gets induced across the conductor.... View Article

Explain the phenomenon of electromagnetic induction. Describe an experiment to show that a current is set up in a closed loop when an external magnetic field passing through the loop increases or decreases.

Electromagnetic induction is a phenomenon of generation of an electric current in a closed circuit by changing the magnetic field. Electric... View Article

Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way these simple electric motors are different from commercial motors?

A current-carrying conductor, when placed in a magnetic field, experiences a force. If the direction of the field and that of the current are... View Article

Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming’s left-hand rule help us to find the direction of the force acting on the current-carrying conductor?

Take a small aluminium rod AB (of about 5 cm). Using two connecting wires suspend it horizontally from a stand, as shown in Fig. Place a strong... View Article

Explain with the help of a labelled diagram the distribution of magnetic field due to a current through a circular loop. Why is it that if a current-carrying coil has n turns the field produced at any point is n times as large as that produced by a single turn?

The right-hand thumb rule is obeyed even in the current-carrying loop. This shows magnetic field lines are around the conducting wire. But the... View Article

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 towards the... 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 field and a... 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 and blows off when... 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 Direct current always flows in one direction but the alternating current reverses its direction periodically. The frequency of AC... View Article

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

c) Both The two conducting stationary brushes draw current from the battery and supply it to the armature of the motor as they touch the outer... 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... 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 solenoid. Outside the coil or... 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 lines of field indicates it.... 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 force experienced by... 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 a current in... 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 of magnetic field... 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 of... 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 the... View Article

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