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प्रश्न
Differentiate between conductors and insulators.
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उत्तर
| Sr. No. | Conductors | Insulators |
| 1. | Those substances through which electricity can flow are called conductors. | Those substances through which electricity cannot flow are called insulators. |
| 2. | Electrical resistances of conductors are very low. | Electrical resistances of insulators are infinitely very high. |
| 3. | They contain a large number of free electrons. | They do not contain free electrons. |
| 4. | Generally, metals are conductors. E.g., silver, copper, aluminium. | Generally, non-metals are insulators. E.g., wood, rubber, plastic. |
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संबंधित प्रश्न
Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.
The magnetic field in a given region is uniform. Draw a diagram to represent it.
The magnetic field inside a long straight solenoid-carrying current ______.
A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is ______.
State Fleming’s left-hand rule.
State qualitatively the effect of inserting an iron core into a current-carrying solenoid.
State whether the following statement is true or false:
The magnetic field inside a long circular coil carrying current well be parallel straight lines.
Fill in the following blank with suitable words:
For a current-carrying solenoid, the magnetic field is like that of a ...........
Describe how you will locate a current-carrying wire concealed in a wall.
The magnetic field lines in the middle of the current-carrying solenoid are?
(a) circles
(b) spirals
(c) parallel to the axis of the tube
(d) perpendicular to the axis of the tube
The front face of a circular wire carrying current behaves like a north pole. The direction of current in this face of circular wire is:
(a) clockwise
(b) downwards
(c) anticlockwise
(d) upwards
For Fleming's left-hand rule, write down the three things that are 90° to each other, and next to each one write down the finger or thumb that represents it.
A horizontal wire carries a current as shown in Figure below between magnetic poles N and S:
Is the direction of the force on the wire due to the magnet:
(a) in the direction the current
(b) vertically downwards
(c) opposite to the current direction
(d) vertically upwards
In the simple electric motor of figure given below, the coil rotates anticlockwise as seen by the eye from the position X when current flows in the coil
Is the current flowing clockwise or anticlockwise around the coil when viewed from above?
If the current in a wire is flowing in the vertically downward direction and a magnetic field is applied from west to east, what is the direction of force in the wire?
Two coils A and B of insulated wire are kept close to each other. Coil A is connected to a galvanometer while coil B is connected to a battery through a key. What would happen if:
a current is passed through coil B by plugging the key?
Explain your answer mentioning the name of the phenomenon involved.
Two coils A and B of insulated wire are kept close to each other. Coil A is connected to a galvanometer while coil B is connected to a battery through a key. What would happen if:
the current is stopped by removing the plug from the key?
Explain your answer mentioning the name of the phenomenon involved.
A flat coil ABCD is freely suspended between the pole of U-shaped permanent magnet with the plane of coil parallel to the magnetic field.
What happens when a current is passed in the coil?
A coil ABCD mounted on an axle is placed between the poles N and S of a permanent magnet as shown in Figure.
- In which direction will the coil begin to rotate when current is passed through the coil in direction ABCD by connecting a battery at the ends A and D of the coil?
- Why is a commutator necessary for continuous rotation of the coil?
- Complete the diagram with commutator, etc. for the flow of current in the coil?
State whether a magnetic field is associated or not around a static charge.
State whether a magnetic field is associated or not around a moving charge.
State under what conditions force acting on a current carrying conductor which is freely suspended in a magnetic field can be maximum.
State under what conditions force acting on a current carrying conductor which is freely suspended in a magnetic field can be Zero.
Which of the following factors affect the strength of force experience by current-carrying conduct in a uniform magnetic field?
A magnetic field directed in north direction acts on an electron moving in east direction. The magnetic force on the electron will act ____________.
The direction of force on a current carrying conductor in a magnetic field is given by ____________.
What does the direction of thumb indicate in the right-hand thumb rule. In what way this rule is different from Fleming’s left-hand rule?
Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming’s left-hand rule help us to find the direction of the force acting on the current carrying conductor?
A simple motor is made in a school laboratory. A coil of wire is mounted on an axle between the poles of a horseshoe magnet, as illustrated.
In the example above, coil ABCD is horizontal and the battery is connected as shown.
- For this position, state the direction of the force on the arm AB.
- Why does the current in the arm BC not contribute to the turning force on the coil?
A copper wire is held between the poles of a magnet
The current in the wire can be reversed. The pole of the magnet can also be changed over. In how many of the four directions shown can the force act on the wire?
An alpha particle enters a uniform magnetic field as shown. The direction of force experienced by the alpha particle is ______.
Two LED bulbs of 10W and 5W are connected in series. If the current flowing through 5W bulb is 0.005A, the current flowing through 10W bulb is ______.
A copper conductor is placed over two stretched copper wires whose ends ate connected to a D.C. supply as shown in the diagram.
- What should be the magnetic poles at the points A and B lying on either side of the conductor to experience the force in the upward direction?
- Name the law used to find these polarities.
