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प्रश्न
Write Fleming’s left hand rule.
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उत्तर
Stretch the index finger, the middle finger, and the thumb of the left hand mutually perpendicular to each other. If the index finger is in the direction of the magnetic field and the middle finger points in the direction of the current, then the thumb will point towards the direction of the force on the conductor.
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संबंधित प्रश्न
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 the rule to determine the direction of a force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it.
Name and state the rule to determine the direction of magnetic field around a straight current-carrying conductor.
List three ways in which the magnetic field strength of a current-carrying solenoid can be increased?
The diagram given below represents magnetic field caused by a current-carrying conductor which is:
(a) a long straight wire
(b) a circular coil
(c) a solenoid
(d) a short straight wire
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
A current-carrying straight wire is held in exactly vertical position. If the current passes through this wire in the vertically upward direction, what is the direction of magnetic field produced by it? Name the rule used to find the direction of magnetic field.
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
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?
force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it.
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.
Name three factors on which the magnitude of force on a current carrying conductor placed in a magnetic field depends and state how does the force depend on the factors stated by you.
State condition when magnitude of force on a current carrying conductor placed in a magnetic field is maximum?
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?
i) Which principle is explained in this figure?
ii) Which rule is used to find out the direction of a force in this principle?
iii) In which machine this principle is used? Draw a diagram showing working of that machine

A flat coil ABCD is freely suspended between the pole of a U-shaped permanent magnet with the plane of coil parallel to the magnetic field.
Name an instrument which makes use of the principle stated above.
Differentiate between conductors and insulators.
State whether a magnetic field is associated or not around a static charge.
State under what conditions force acting on a current carrying conductor which is freely suspended in a magnetic field can be maximum.
A current-carrying conductor is held in an exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should be passed in the conductor:
The direction of force on a current carrying conductor in a magnetic field is given by ____________.
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?
Assertion (A): A magnetic field exerts a force on a moving charge in the same direction as the direction of the field itself.
Reason (R): The direction of force is given by Fleming’s left-hand rule.
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?
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.

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The graph (fig A) illustrates the correlation between the number of protons (x-axis) and the number of neutrons (y-axis) for elements A, B, C, D, and E in the periodic table. These elements are denoted by the letters rather than their conventional symbols. When the element C, depicted in the graph, undergoes radioactive decay, it releases radioactive rays. When these rays are directed into the plane of the paper in the presence of a magnetic field, as indicated in the fig B, they experience deflection, causing them to move upwards.
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Name the law used to identify the radioactive radiation emitted by the element.

