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प्रश्न
Draw a labelled diagram to make an electromagnet from a soft iron bar. Mark the polarity at its ends in your diagram. What precaution would you observe while making it?
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उत्तर
The labelled diagram is shown in figure.
Precaution: The source of current must be the D. C. battery.
संबंधित प्रश्न
An emf of 2V is induced in a coil when the current in it is changed from 0A to 10A in 0·40 sec. Find the coefficient of self-inductance of the coil.
State whether the following statement are true or false:
A motor works on the principle electric generator?
Name and state the law which determines the direction of induced current.
or
State Fleming’s right-hand rule.
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
D.C. motor ______.
What is an electromagnet?
Using Ampere's law, obtain an expression for the magnetic induction near a current-carrying straight infinitely long wire.
An induced current of 2.5 mA flows through a single conductor of resistance 100 Ω. Find out the rate at which the magnetic flux is cut by the conductor.
A generator has an e.m.f. of 440 Volt and internal resistance of 4000 hm. Its terminals are connected to a load of 4000 ohm. The voltage across the load is ______.
AB is a coil of copper wire having a large number of turns. The ends of the coil are connected with a galvanometer as shown. When the north pole of a strong bar magnet is moved towards end B of the coil, a deflection is observed in the galvanometer.
- State the reason for using galvanometer in the activity and why does its needle deflects momentarily when magnet is moved towards the coil.
- What would be observed in the galvanometer in a situation when the coil and the bar magnet both move with the same speed in the same direction? Justify your answer.
- State the conclusion that can be drawn from this activity.
Will there be any change in the momentary deflection in the galvanometer if number of turns in the coil is increased and a more stronger magnet is moved towards the coil?
OR
What is electromagnetic induction? What is observed in the galvanometer when a strong bar magnet is held stationary near one end of a coil of large number of turns? Justify your answer.
