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प्रश्न
How does an electromagnet differ forma permanent magnet?
उत्तर
| Electromagnet | Permanent magnet | ||
| 1. | It is a temporary magnet. |
1.
|
As the name suggests, it is a permanent magnet. |
| 2. | It can produce very strong magnetic force. | 2. | It produces a comparatively weak magnetic field. |
| 3. | Its polarity can be changed by changing the direction of current in the coil. | 3. | Its polarity is fixed and cannot be changed. |
| 4. | Its strength can be changed by changing the number of turns or by changing the current. | 4. | Its strength cannot be changed. |
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संबंधित प्रश्न
Electric field intensity in free space at a distance ‘r’ outside the charged conducting sphere of radius ‘R’ in terms of surface charge density ‘ a ’ is............................
(a)`sigma / in_0[R/r]^2`
(b)`in_0/sigma[R/r]^2`
(c)`R/r[sigma/in_0]^2`
(d)`R/sigma[r/in_0]^2`
A solenoid of length 1.5 m and 4 cm in diameter possesses 10 turns per metre. A current of 5 A is flowing through it. The magnetic induction at a point inside the solenoid along the axis is ............................. .
(μ0 = 4π × 10-7 Wb/Am)
- π × 10-5 T
- 2π × 10-5 T
- 3π × 10-5 T
- 4π × 10-5 T
State the factors on which the strength of an electromagnet depends. How does it depend on these factors?
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?
State Fleming’s Right Hand Rule.
You have been provided with a solenoid AB.
(i) What is the polarity at end A?
(ii) Give one advantage of an electromagnet over a permanent magnet.
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.
(i) State your observation, when current is switched on.
(ii) Give an explanation for your observation in (i).
(iii) State the rule, which will help you to find the motion of rotation of coil.
(iv) In which position will the coil ultimately come to rest?
(v) State four ways of increasing the magnitude of force acting on the coil.
An electron moves on a straight-line path XY as shown in the figure. The coil abcd is adjacent to the path of the electron. What will be the direction of the current, if any, induced in the coil?
A square coil of side 30 cm with 500 turns is kept in a uniform magnetic field of 0.4 T. The plane of the coil is inclined at an angle of 30° to the field. Calculate the magnetic flux through the coil.
