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प्रश्न
In the Activity shown below, how do we think the displacement of rod AB will be affected if
- current in rod AB is increased
- a stronger horse-shoe magnet is used
- length of the rod AB is increased?
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उत्तर
A current-carrying conductor placed in a magnetic field experiences a force. The magnitude of force increases with the amount of current, strength of the magnetic field, and the length of the conductor. Hence, the magnetic force exerted on rod AB and its deflection will increase if,
- The current in rod AB is increased.
- A stronger horse-shoe magnet is used.
- Length of rod AB is increased.
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संबंधित प्रश्न
When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
Will the compass needle show deflection when the switch in the circuit shown by figure is closed?
Name the scientist who discovered the magnetic effect of current.
Fill in the following blank with suitable words:
If a coil is viewed from one end, and the current flows in a clockwise direction, then this end is a ........... pole.
If the direction of electric current in a solenoid when viewed from a particular end is anticlockwise, then this end of solenoid will be:
(a) west pole
(b) south pole
(c) north pole
(d) east pole
The magnetic effect of current was discovered by:
(a) Maxwell
(b) Fleming
(c) Oersted
(d) Faraday
For the coil in the diagram below, when the switch is pressed:
(a) what is the polarity of end A?
(b) which way will the compass point then?
The direction of current flowing in the coil of an electromagnet at its two ends X and Y are as shown below:
What is the polarity of end X?
What is the polarity of end Y?
Name and state the rule which you have used to determine the polarities.
Answer the following question:
State the effect on the magnetic needle in Oersted’s experiment when:
(a) the current is passed through the wire.
(b) the current through the wire is increased
(c) the current through the wire is reversed.
Read the given passage and answer the following questions:
The home electrical connection consists of ‘live’, ‘neutral’ and ‘earth’ wires. The ‘live’ and the ‘neutral’ wires have potential difference of 220 V. The ‘earth’ is connected to ground. Due to a fault in the equipment or if the plastic coating on the ‘live’ and the ‘neutral’ wires gives a way the two wires come in contact with each other and a large current flows through it producing heat. If any inflammable material (such as wood, cloth, plastic, etc.) exists around that place it can catch fire. Therefore a fuse wire is used as a precautionary measure.
- Name the two wires having potential difference of 220 V.
- What is a short circuit?
- Write the function of a fuse.
Explain the magnetic field created around a straight current carrying conductor with the help of a diagram.
What is that instrument which can detect the presence of electric current in a circuit?
A magnetic compass shows a deflection when placed near a current carrying wire. How will the deflection of the compass get affected if the current in the wire is increased? Support your answer with a reason.
Boojho made an electromagnet by winding 50 turns of wire over an iron screw. Paheli also made an electromagnet by winding 100 turns over a similar iron screw. Which electromagnet will attract more pins? Give reason.
______ are also used to remove splinters of steel or iron in hospitals dealing with eye injuries.
______ cells cannot be recharged after use.
The figure given below shows the magnetic field around the conductor. Study it and answer the questions:
- What changes are caused by increasing current?
- What do you see when the magnetic needle is kept a little away from the wire?
- In the second part of the figure, the iron filings arrange themselves in a circular manner around the wire. Why does this happen?
A student was asked to perform an experiment to study the force on a current carrying conductor in a magnetic field. He took a small aluminium rod AB, a strong horse shoe magnet, some connecting wires, a battery and a switch and connected them as shown. He observed that on passing current, the rod gets displaced. On reversing the direction of current, the direction of displacement also gets reversed. On the basis of your understanding of this phenomenon, answer the following questions:
- Why does the rod get displaced on passing current through it?
- State the rule that determines the direction of the force on the conductor AB.
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- If the U-shaped magnet is held vertically and the aluminium rod is suspended horizontally with its end B towards due north, then on passing current through the rod from B to A as shown, in which direction will the rod be displaced?
- Name any two devices that use current carrying conductors and magnetic fields.
OR
Draw the pattern of magnetic field lines produced around a current carrying straight conductor held vertically on a horizontal cardboard. Indicate the direction of the field lines as well as the direction of current flowing through the conductor.
