When an electric current flows through a conductor (like a wire), it produces a magnetic field around it. This is called the magnetic effect of electric current.
Key Concepts:
- Magnetic Field Around a Wire:-
- Current in a wire produces a magnetic field.
- Right-Hand Thumb Rule helps determine the direction of the field.
- Solenoid:-
- A coil of wire that creates a strong magnetic field when current flows through it. It behaves like a magnet.
- Electromagnet:-
- A temporary magnet created by passing current through a coil around an iron core.
- Force on a Current-Carrying Conductor: -
- A wire carrying current in a magnetic field experiences a force.
- Fleming's Left-Hand Rule determines the direction of the force.
Applications:
- Electric Motors:Use the force on current-carrying conductors in a magnetic field to produce motion.
- Electromagnets:Used in devices like cranes to lift heavy magnetic materials.
Practice Questions PDF
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Questions on Magnetic Effects of Electric Current
Showing 31–60 of 21531.What will happen to the magnetic field lines around a straight current-carrying conductor if the current is increased? 32.Why is an AC generator more commonly used than a DC generator for power generation at power stations? 33.Explain how the direction of induced current can be predicted using Fleming's Right-Hand Rule. 34.Which of the following is not a property of magnetic field lines? 35.A compass needle is placed on a table. A current-carrying wire is brought directly above the compass needle. If the current flows from west to east, what will be the direction of deflection of the north pole of the compass? 36.Why does a motor usually have a cylindrical soft iron core inside its armature coil? 37.Consider a current-carrying wire bent into a circular loop. If the current flows clockwise, what is the direction of the magnetic field at the center of the loop? 38.What is the purpose of the insulated covering on electric wires? 39.Explain the term 'short-circuiting' in a domestic electric circuit and its potential hazards. 40.An electric fuse has a rating of 5A. Can it be used in a circuit that draws a maximum current of 7A? Justify your answer. 41.A strong bar magnet is dropped vertically downwards into a long, thick copper pipe. Describe the observed motion of the magnet and explain why. 42.Why are the pole pieces of an electric motor made concave? 43.Which of the following would NOT affect the strength of the magnetic field produced by a current-carrying straight wire? 44.A wire loop is moved away from a current-carrying solenoid. In which direction will the induced current flow in the loop, if the solenoid's current creates a North pole on the side facing the loop? 45.What is the primary difference in the internal structure of an AC generator compared to a DC generator? 46.Describe how a galvanometer can be converted into an ammeter. 47.Consider a scenario where a metal rod is dropped through a strong magnetic field. What phenomenon occurs, and what is its implication on the rod's motion? 48.Why is a fuse always connected in the live wire of an electric circuit? 49.What would happen if the brushes of a DC motor were made of insulating material instead of conducting material? 50.A beam of alpha particles (positively charged) is projected horizontally towards the east. If a uniform magnetic field exists vertically upwards, in what direction will the alpha particles be deflected? 51.Explain why two magnetic field lines never intersect each other. 52.A current-carrying solenoid is compressed, reducing its length while keeping the number of turns and current constant. How does this affect the magnetic field strength inside it? 53.A circular loop carries current in a clockwise direction. What is the polarity of the face of the loop when viewed from the front? 54.If a straight conductor carries current vertically downwards, what is the direction of the magnetic field lines when viewed from a point to the east of the conductor? 55.A student connects a bulb, a battery, and a switch in series. When the switch is closed, the bulb glows. Now, he brings a compass needle near the wire. What will he observe and why? 56.Why is AC preferred over DC for long-distance transmission of electric power? 57.What is the significance of the 'earthing' wire in domestic circuits? 58.Explain the phenomenon of 'overloading' in a domestic electric circuit. 59.Which safety device is designed to protect electrical appliances from high currents due to overloading or short-circuiting? 60.Why is it dangerous to touch a live wire with bare hands?