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प्रश्न
The diagram shows a rectangular coil ABCD, suspended freely between the concave pole pieces of a permanent horseshoe magnet, such that the plane of the coil is parallel to the magnetic field.
- State your observation when the current is switched on.
- Give an explanation for your observation in (i).
- State the rule, which will help you to find the motion of rotation of the coil.
- In which position will the coil ultimately come to rest?
- State four ways of increasing the magnitude of force acting on the coil.
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उत्तर
- The coil ABCD will turn. The arm AB of the coil will move out of the plane of the paper and arm CD into the plane of the paper. Thus, the coil will turn in the anticlockwise direction.
- A magnetic field is set up by the coil due to the passage of electric current. The magnetic field of the coil is at right angles to the magnetic field of the permanent magnet. Thus, a magnetic couple acts, which turns the coil.
- Fleming’s left rule: It states: Stretch the thumb, the forefinger, and the middle finger of the left hand such that the forefinger points in the direction of the magnetic field and the middle finger points in the direction of the current. Then, the thumb points in the direction of motion of the conductor.
- The coil will come to rest at right angles to the direction of the magnetic field.
-
- By increasing the number of turns in the coil.
- By increasing the area of the cross-section of the coil.
- By placing a laminated soft iron core within the coil.
- By increasing the magnitude of the current coil.
APPEARS IN
संबंधित प्रश्न
Describe different ways to induce current in a coil of wire.
How is the working of an electric bell affected, if alternating current be used instead of direct current?
In which of the following case does the electromagnetic induction occur?
A loop of wire is held near a magnet.
Fig. shows a simple form of an A.C. generator.
(a) Name the parts labeled A and B.
(b) What would be the effect of doubling the number of turns on the coil if the speed of rotation remains unchanged?
(c) Which of the output terminals is positive if the coil is rotating in the
direction shown in the diagram (anticlockwise)?
( d ) What is the position of the rotating coil when p.d. across its ends is zero? Explain why p.d. is zero when the coil is at this position .
(e) Sketch a graph showing how the p.d. across the ends of the rotating coil varies with time for an A.C. dynamo.
( f) On th e same sheet of paper and vertically below the first graph using the same time scale, sketch graphs to show the effect of
(i) Doubling the speed of rotation and at the same time keeping
the field and the number of turns constant,
(ii ) Doubling the number of turns on the coil and at the same time
doubling the speed of rotation of the coil, keeping th e speed
constant.
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 ______.
Write Fleming’s right hand thumb rule with the help of diagram.
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 ______.
There is a uniform magnetic field directed perpendicular and into the plane of the paper. An irregular shaped conducting loop is slowly changing into a circular loop in the plane of the paper. Then ______.
Ansari Sir was demonstrating an experiment in his class with the setup as shown in the figure below.
A magnet is attached to a spring. The magnet can go in and out of the stationary coil. He lifted the Magnet and released it to make it oscillate through the coil.
Based on your understanding of the phenomenon, answer the following question.
What is the principle which Ansari Sir is trying to demonstrate?
Show that for a given positive ion species in a cyclotron, (i) the radius of their circular path inside a dee is directly proportional to their speed, and (ii) the maximum ion energy achievable is directly proportional to the square of the magnetic induction.
