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प्रश्न
What is an electromagnet? Describe the construction and working of an electromagnet with the help of a labelled diagram.
उत्तर
Electromagnet:
It is a magnet that works on the principle of magnetic effect of current.
A temporary magnet consisting of a long coil of insulated copper wire wrapped around a soft iron core is called an electromagnet.
Construction and working:
We take a rod NS of soft iron and wind coil C of insulated copper wire around it. When we connect the two ends of the copper coil to a battery, an electromagnet is formed. The iron rod inside the coil becomes a strong electromagnet on passing a current. The magnetic field produced by an electromagnet is very strong.
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संबंधित प्रश्न
The following diagram shows a fixed coil of several turns connected to a center zero galvanometer G and a magnet NS which can move in the direction shown in the diagram.
- Describe the observation in the galvanometer if
- The magnet is moved rapidly,
- The magnet is kept still after it has moved into the coil
- The magnet is then rapidly pulled out the coil.
- How would the observation in (i) of part (a) change if a more powerful magnet is used?
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.
Transformer______.
Complete the following diagram of a transformer and name the parts labeled A and B. Name the part you have drawn to complete the diagram . What is the material of this part? In this transformer a step-up or step-down? Why?
Answer the following:
State the principles of the electric motor and electric generator.
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?
Establish the fact that the relative motion between the coil and the magnet induces an emf in the coil of a closed circuit.
A coil of 200 turns carries a current of 4 A. If the magnetic flux through the coil is 6 x 10-5 Wb, find the magnetic energy stored in the medium surrounding the coil.
If the sun radiates energy at the rate of 3.6 × 1033 ergs/sec the rate at which the sun is loosing mass is given by ______.
A current I = 10 sin(100π t) A is passed in first coil, which induces a maximum e.m.f of 5π volt in second coil. The mutual inductance between the coils is ______.
The charge will flow through a galvanometer of resistance 200Ω connected to a 400Ω circular coil of 1000 turns wound on a wooden stick 20 mm in diameter, if a magnetic field B = 0.012 T parallel to the axis of the stick decreased suddenly to zero, is near ______.
