Electromagnetic Induction
Electromagnetic Induction If a wire is moved through a magnetic field in such a way that it cuts the magnetic lines of force, a voltage ... Read More
Moving coil loud speaker (physics)
Moving coil loud speaker When the varying current is supplied into the coil, the coil is magnetized and vibrates backwards and forwards, with the same ... Read More
Mode of action telephone receiver (physics)
Mode of action telephone receiver (physics) The varying current from the microphone passes through the coil of electromagnets, soft iron gets magnetized and pull the ... Read More
Electric bell
Electric bell When the switch is closed, current flows through the circuit and the core become magnetized The iron armature is attracted towards the magnetized ... Read More
Magnetic field pattern due to solenoid
Magnetic field pattern due to solenoid Please Subscribe to promote this website. Subscription is free Share with a friend Your comments are highly welcome Thank ... Read More
Magnetic field pattern due to parallel conductors
Magnetic field pattern due to parallel conductors Please Subscribe to promote this website. Subscription is free Share with a friend Your comment is valuable ... Read More
Magnetic field pattern due to a coil
Magnetic field pattern due to a coil Please Subscribe to promote this website. Subscription is free Share with a friend Your comment is valuable Your ... Read More
Magnetic field on straight conductor carrying current into or out of the paper
Magnetic field pattern on straight conductor carrying current into or out of the paper Please Subscribe to promote this website. Subscription is free Share with ... Read More
Magnetic flux pattern due to soft iron in earth’s horizontal magnetic field
Magnetic flux pattern due to soft iron in earth’s horizontal magnetic field Please Subscribe to promote this website. Subscription is free Share with a friend ... Read More
Magnetic flux pattern of a horizontal bar magnet in earth’s magnetic field
Magnetic flux pattern of a horizontal bar magnet in earth’s magnetic field South Pole, S, of bar magnet facing to north (attraction occurs) North Pole, ... Read More
Experiment to determine magnetic meridian
Experiment to determine magnetic meridian A permanent bar magnet is suspended on a retort stand using a thread and allowed to settle. The vertical plane ... Read More
An experiment to determine the magnetic field pattern of bar magnet using iron fillings.
An experiment to determine the magnetic field pattern of bar magnet using iron fillings. A cardboard is placed on a magnet and iron fillings sprinkled ... Read More
Soft and hard magnetic substances
Soft and hard magnetic substances Soft magnetic materials are substance that are easily magnetized and easily lose magnetism, e.g. soft iron. Soft magnetic materials are ... Read More
Storing magnets
Storing magnets Small pieces of soft iron called keepers are placed across opposite poles of two bar magnets These iron keepers become induced magnets and ... Read More
Methods of demagnetization
Demagnetization Demagnetization is the process through which magnets lose their magnetism Demagnetization result in scattering molecular magnets to face in randomly. Methods of demagnetization ... Read More
Magnetic saturation
Magnetic saturation This is the maximum level of magnetization when the resultant magnetic axes of all domains in magnetic material are aligned with the magnetizing ... Read More
Magnetization or methods of making a magnet
Magnetization This is a process by which randomly arranged molecular magnet of a ferromagnetic material are arranged to point in one direction. Methods of magnetization ... Read More
Magnetic domain theory
Magnetic domain theory A magnet is made us of tiny molecular magnets called dipole arranged in groups called magnetic domains, lined up with their N-poles ... Read More
How to test for polarity of am magnet
Testing for polarity of a pole A known pole of magnet is brought near the ends of a material suspected to be a magnet. If ... Read More
Laws of magnetism
Laws of magnetism Like poles of magnets repel; g. when a north pole is brought near a north pole or a south pole brought near ... Read More
What are uses of magnets
Uses of magnets In construction of cycle dynamos, telephones, loud speaker, electric meters, current measuring instruments. To remove metal splinters from oil engine For door ... Read More
What is magnetism?
Magnetism is the ability of substances to attract and/or repel others Please Subscribe to promote this website. Subscription is free Share with a friend Your ... Read More
(ii) Sketch graphs to show the time-dependence of supplied voltage and the current in the circuit.
Sketch graphs to show the time-dependence of supplied voltage and the current in the circuit. Please Subscribe to promote this website. Subscription is free Share ... Read More
Discuss the factors which determine the maximum e.m.f generated by a dynamo.
Discuss the factors which determine the maximum e.m.f generated by a dynamo. Induced e.m.f, E = 2πfNBAsin 2πft Maximum e.m.f, E0 = 2πfNBA Thus maximum ... Read More
Give two practical applications of this Eddy currents
Give two practical applications of this Eddy currents damping of moving coil meters melting metals in induction furnaces breaking in electric train Please Subscribe ... Read More
Explain the term back e.m.f in a d.c motor.
Explain the term back e.m.f in a d.c motor. As the motor rotates the magnetic field, the flux linking changes. This induces an e.mf in ... Read More
Explain the advantages of a.c over d.c in power transmissions
Explain the advantages of a.c over d.c in power transmissions c can easily be stepped up and down c is easy to generate c can ... Read More
Describe an experiment to demonstrate mutual induction
Describe an experiment to demonstrate mutual induction Coil A and B are placed close to each other. When K is closed bulb P lights. Hence ... Read More
Describe how you would determine the value of the earth’s magnetic flux density at a place, using a search coil.
A coil of known number of turns, N (about 100) and area A is connected to a calibrated ballistic galvanometer so that the total resistance ... Read More
What is hysteresis loss ?
What is hysteresis loss ? Hysteresis loss is the loss in energy due to the magnetic domains from one direction to the other as current ... Read More
Describe with aid of a labelled diagram the structure and action of a hot wire ammeter.
Describe with aid of a labelled diagram the structure and action of a hot wire ammeter. The current flows through a fine resistance-wire XY, which ... Read More
What is meant by the terms reactance and impedance as applied to alternating currents.
What is meant by the terms reactance and impedance as applied to alternating currents. Reactance is non resistive opposition to the flow of a.c in ... Read More
Describe with the aid of a diagram, an absolute method of measuring current.
Describe with the aid of a diagram, an absolute method of measuring current. Current balance is based on principles of moments The apparatus setup is ... Read More
A rectangular coil of N turns, length, L and breadth, b, carrying a current, I, is placed with its plane making a angle, θ, to a uniform magnetic field of flux density, B. Derive the expression for torque exerted on the coil.
A rectangular coil of N turns, length, L and breadth, b, carrying a current, I, is placed with its plane making a angle, θ, to ... Read More
Describe the structure and mode of operation of the repulsion type moving iron meter.
Describe the structure and mode of operation of the repulsion type moving iron meter. When a current is passed through the coil, the iron rods ... Read More
Explain why a capacitor in a circuit blocks the flow of direct current but allows the flow of alternating current
Explain why a capacitor in a circuit blocks the flow of direct current but allows the flow of alternating current. When a capacitor is connected ... Read More
(iii) Sketch using the same axes the graphs of charge Q on the capacitor and current I in the circuit against time.
Sketch using the same axes the graphs of charge Q on the capacitor and current I in the circuit against time. Explanation of the curve ... Read More
What is a sinusoidal alternating current?
What is a sinusoidal alternating current? A sinusoidal a.c is aperiodic current whose time dependence is given by sine function. Please Subscribe to promote ... Read More
Why when a plate of copper is pushed into a strong magnetic field between the poles of a powerful electromagnet, considerable resistance to the motion is felt, but no such effect is felt with a sheet of glass.
Why when a plate of copper is pushed into a strong magnetic field between the poles of a powerful electromagnet, considerable resistance to the motion ... Read More
Describe with aid of a diagram, an experiment to verify Faraday’s law of electromagnetic induction
Describe with aid of a diagram, an experiment to verify Faraday’s law of electromagnetic induction X and Y are brush contact. A copper rod which ... Read More
Describe an experiment to measure the magnetic flux density between the pole pieces of a strong magnet.
Describe an experiment to measure the magnetic flux density between the pole pieces of a strong magnet. A search coil is connected to a ballistic ... Read More
Define the ampere
Define the ampere The ampere is steady current flowing in negligible cross-section, one meter apart in vacuum when the force between them is 2 x ... Read More
(iii) Explain why the current in the primary coil of a transformer increases when the secondary is connected to the load.
Explain why the current in the primary coil of a transformer increases when the secondary is connected to the load. When load is connected to ... Read More
Describe the structure and mode of action of the deflected magnetometer
Describe the structure and mode of action of the deflected magnetometer It consists of a small compass needle (small magnet) which is pivoted on a ... Read More
Magnetic variance
Magnetic variance Magnetic variation is the angle between the magnetic and geographical meridians. Or, angle between the earth’s magnetic axis and geographical axis. Please Subscribe ... Read More
Magnetic meridian
Magnetic meridian Magnetic meridian is a vertical plane in which a freely suspended magnet sets itself. Please Subscribe to promote this website. Subscription is free ... Read More
Magnetic meridian
Magnetic meridian. Magnetic meridian is a vertical plane in which a freely suspended magnet sets itself. Please Subscribe to promote this website. Subscription is ... Read More
How can a d.c. generator be converted into an a.c. generator.
How can a d.c. generator be converted into an a.c. generator. To convert a d.c. generator to an a.c. generator, the ends of the rectangular ... Read More
How can a d.c. generator be converted into an a.c. generator.
How can a d.c. generator be converted into an a.c. generator. To convert a d.c. generator to an a.c. generator, the ends of the rectangular ... Read More
Describe briefly the factors that determine the peak value of the induced e.m.f in d.c generator
Describe briefly the factors that determine the peak value of the induced e.m.f in d.c generator The peak value of induced e.m.f increases with increase ... Read More
(ii) Describe with the aid of a labelled diagram the structure and mode of operation of a d.c generator.
Describe with the aid of a labelled diagram the structure and mode of operation of a d.c generator. B1 and B2 are carbon brushes, C1 ... Read More
what is the difference between a motor and a dynamo?
What is the difference between a motor and a dynamo? A dynamo converts mechanical energy to electrical energy while a motor converts electrical energy into ... Read More
Describe how a thermocouple ammeter is used to measure an alternating current
Describe how a thermocouple ammeter is used to measure an alternating current P and Q are dissimilar wires Current to be measured is passed through ... Read More
Sketch using the same axes the variation of applied voltage and current through the inductor with time
Sketch using the same axes the variation of applied voltage and current through the inductor with time Please Subscribe to promote this website. Subscription ... Read More
Explain the structural modification needed to convert an a.c. generator into a d.c. generator.
Explain the structural modification needed to convert an a.c. generator into a d.c. generator. The slip rings are replaced by commutators and the brushes are ... Read More
Write down and expression for the e.m.f generated by a dynamo and use it to identify the factors which determine the maximum e.m.f.
Write down and expression for the e.m.f generated by a dynamo and use it to identify the factors which determine the maximum e.m.f. Induced e.m.f ... Read More
Describe the feature of earth’s magnetic field
Describe the feature of earth’s magnetic field Geographical meridian is the vertical plane containing the geographical axis Magnetic meridian is the vertical plane containing magnetic ... Read More
Describe an experiment to determine the magnetic flux density of a uniform magnetic field using a search coil and ballistic galvanometer
Describe an experiment to determine the magnetic flux density of a uniform magnetic field using a search coil and ballistic galvanometer A search coil of ... Read More
Define magnetic flux density.
Define magnetic flux density. Magnetic flux is the force acting on conductor of length 1m and carrying of 1A placed perpendicular to magnetic field. Please ... Read More
Explain the steps taken to minimize power losses in electric power transformation.
Explain the steps taken to minimize power losses in electric power transformation. - Voltage generated is stepped up using a transformer so as to transmit ... Read More