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How does the magnetic effect of electric current help in the working of an electric bell? Explain with the help of a diagram. - Science

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How does the magnetic effect of electric current help in the working of an electric bell? Explain with the help of a diagram.

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उत्तर

The door bell or the electric bell makes use of the principle of an electromagnet. A horseshoe type of electromagnet is used in an electric bell which is connected to the source of current through a switch. It has a metallic gong, a hammer to strike the gong and screw attached to a soft iron strip.

When the button is pressed, the circuit is complete and the hammer gets attracted to the gong thereby striking it to produce a ringing sound.

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  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 14: Electric Current and Its Effects - LONG ANSWER QUESTIONS [पृष्ठ ७९]

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एनसीईआरटी एक्झांप्लर Science [English] Class 7
पाठ 14 Electric Current and Its Effects
LONG ANSWER QUESTIONS | Q 19. | पृष्ठ ७९

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A coil is connected to a galvanometer. When the N-pole of magnet is pushed into the coil, the galvanometer deflected to the right. What deflection, if any, is observed when:  

 the N-pole is removed?




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In the Activity shown below, how do we think the displacement of rod AB will be affected if

  1. current in rod AB is increased
  2. a stronger horse-shoe magnet is used
  3. length of the rod AB is increased?
  • 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 horse-shoe magnet in such a way that the rod lies between the two poles with the magnetic field directed upwards. For this put the north pole of the magnet vertically below and south pole vertically above the aluminium rod (Fig.).
  • Connect the aluminium rod in series with a battery, a key and a rheostat.
  • Now pass a current through the aluminium rod from end B to end A.
  • What do you observe? It is observed that the rod is displaced towards the left. You will notice that the rod gets displaced.
  • Reverse the direction of current flowing through the rod and observe the direction of its displacement. It is now towards the right.
  • Why does the rod get displaced?


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AgCI : White :: CuI2 : ___________


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