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 1–30 of 2151.Why is the current in the neutral wire usually zero when all appliances in a domestic circuit are switched off? 2.A bar magnet is moved towards a coil of wire. What factors influence the magnitude of the induced current? 3.An electric motor's armature current is increased. What is the effect on its output mechanical power? 4.What kind of magnetic field is produced by a current-carrying circular loop at its center? 5.How does a fuse differ from a circuit breaker in terms of functionality and reusability? 6.What is the direction of the magnetic force on a straight current-carrying wire placed in a uniform magnetic field, if the current flows into the page and the magnetic field points from left to right? 7.Explain why it is not advisable to use bare wires for electrical connections in homes. 8.If a small coil is placed inside a large current-carrying solenoid such that their axes are parallel, and the current in the solenoid is gradually increased, will an EMF be induced in the small coil? 9.An electric current is flowing in a straight conductor from north to south. What is the direction of the magnetic field lines when viewed from a point directly below the conductor? 10.How does increasing the number of turns in the coil of an electromagnet affect its strength? 11.A copper rod is moved towards a solenoid with its North pole facing the rod. What is the direction of the induced current in the rod if any? 12.Why are some devices in domestic circuits connected to the earth wire? 13.Two straight, parallel conductors carry current in opposite directions. Describe the force between them. 14.A square loop of wire is moved into a uniform magnetic field, then through it, and finally out of it. Describe when an induced current will flow in the loop. 15.What is the primary function of a circuit breaker? 16.A permanent magnet is used in a galvanometer. What is the role of this magnet? 17.Which type of generator is used to produce electricity for most household and industrial purposes? 18.Why is it essential to use a low melting point material for a fuse wire? 19.What would be the effect on the magnetic field inside a solenoid if both the current and the number of turns per unit length are halved? 20.A wire of length L carrying current I is placed in a uniform magnetic field B. What is the condition for the force on the wire to be maximum? 21.Which of the following determines the direction of the magnetic field produced by a straight current-carrying conductor? 22.A transformer works on the principle of: 23.This makes sense. 24.A student places two bar magnets such that their North poles face each other at a small distance. Now, a current-carrying wire is placed exactly between them, perpendicular to the line joining the poles. If the current flows vertically upwards, what will be the direction of the force experienced by the wire? 25.If an electron beam is directed horizontally towards the north and enters a magnetic field pointing vertically downwards, what will be the direction of deflection of the electron beam? 26.A proton enters a uniform magnetic field directed into the page. If the proton's velocity is to the right, what is the direction of the magnetic force on the proton? 27.How does increasing the area of a coil affect the induced EMF in a generator, assuming other factors remain constant? 28.Why are circuit breakers often preferred over fuses in modern electrical installations? 29.Describe the working principle of an electric bell, relating it to the magnetic effects of current. 30.A copper wire is held between the poles of a magnet. If the wire is moved upwards, an induced current is observed. What happens if the wire is moved downwards with the same speed?