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Physics Past Questions and Answers
Topic: A.C. and D.C generators
Classroom
Jamb
Exam year:
Exam year
Question type:
Question type
Objective
Theory
Topics:
Topics
[1] Measurements and Units
[1].1 Length, area and volume
[1].1.1 Metre rule
[1].1.2 Measuring cylinder
[1].1.3 Screw guage
[1].1.4 Micrometer
[1].1.5 Vernier calipers
[1].2 Mass
[1].2.1 Unit of mass
[1].2.2 Use of Simple beam balance
[1].2.3 Concept of beam balance
[1].3 Time
[1].3.1 Unit of time
[1].3.2 Time-measuring devices
[1].4 Fundamental physical quantities
[1].5 Derived physical quantities and their units
[1].6 Dimensions
[1].6.1 Definition of dimensions
[1].7 Limitations of experimental measurements
[1].7.1 Accuracy of measuring instruments
[1].7.2 Simple estimation of errors
[1].7.3 Significant figures
[1].7.4 Standard form
[1].8 Measurement, position, distance and displacement
[1].8.1 Concept of displacement
[1].8.2 Distinction between distance and displacement
[1].8.3 Concept of position and coordinates
[1].8.4 Frame of reference
[2] Scalars and Vectors
[2].1 Definition of Scalar and vector quantities
[2].2 Examples of scalar and vector quantities
[2].3 Relative velocity
[2].4 Resolution of vectors into two perpendicular directions
[3] Motion
[3].1 Types of motion
[3].1.1 Translational motion
[3].1.2 Oscillatory motion
[3].1.3 Rotational motion
[3].1.4 Spin motion
[3].1.5 Random motion
[3].2 Relative motion
[3].3 Causes of motion
[3].4 Types of force
[3].4.1 Contact
[3].4.2 Force field
[3].5 Linear motion
[3].5.1 Speed
[3].5.2 Velocity
[3].5.3 Acceleration
[3].5.4 Equations of uniformly accelerated motion
[3].5.5 Motion under gravity
[3].5.6 Distance-time graph and Velocity time graph
[3].5.7 Instantaneous velocity and Acceleration.
[3].6 Projectiles
[3].6.1 Calculation of range
[3].6.2 Calculation of maximum height
[3].6.3 Calculation of time of flight from the ground and a height
[3].6.4 Applications of projectile motion
[3].7 Newton's laws of motion
[3].7.1 Inertia
[3].7.2 Mass and force
[3].7.3 Relationship between mass and acceleration
[3].7.4 Impulse and momentum
[3].7.5 Force - time graph
[3].7.6 Conservation of linear momentum
[3].8 Motion in a circle
[3].8.1 Angular velocity and angular acceleration
[3].8.2 Centripetal and centrifugal forces
[3].8.3 Applications
[3].9 Simple Harmonic Motion (S.H.M)
[3].9.1 Definition and explanation of Simple harmonic motion
[3].9.2 Examples of systems that execute S.H.M
[3].9.3 Period of S.H.M
[3].9.4 Frequency of S.H.M
[3].9.5 Amplitude of S.H.M
[3].9.6 Velocity and acceleration of S.H.M
[3].9.7 Simple treatment of energy change in S.H.M
[3].9.8 Simple treatment of force vibration and resonance
[4] Gravitational field
[4].1 Newton’s law of universal gravitation
[4].2 Gravitational potential
[4].3 Conservative and non-conservative fields
[4].4 Acceleration due to gravity
[4].5 Variation of g on the earth’s surface
[4].6 Distinction between mass and weight; escape velocity
[4].7 Parking orbit and weightlessness
[5] Equilibrium of Forces
[5].1 Equilibrium of particles
[5].1.1 Equilibrium of coplanar forces
[5].1.2 Triangles and polygon of forces
[5].1.3 Lami's theorem
[5].2 Principles of moments
[5].2.1 Moment of a force
[5].2.2 Simple treatment and moment of a couple (torque)
[5].2.3 Applications
[5].3 Conditions for equilibrium of rigid bodies under the action of parallel and non-parallel forces
[5].3.1 Resolution and composition of forces in two perpendicular directions
[5].3.2 Resultant and equilibrant
[5].4 Centre of gravity and stability
[5].4.1 Stable, unstable and neutral equilibrium
[6] (a) Work, Energy and Power
[6].1 Work, Energy and Power
[6].1.1 Definition of work, energy and power
[6].1.2 Forms of energy
[6].1.3 Conservation of energy
[6].1.4 Qualitative treatment between different forms of energy
[6].1.5 Interpretation of area under the force-distance curve
[6].2 Energy and society
[6].2.1 Sources of energy
[6].2.2 Renewable and non-renewable energy
[6].2.3 Uses of energy
[6].2.4 Energy and development
[6].2.5 Energy diversification
[6].2.6 Environmental impact of energy
[6].2.7 Energy crises
[6].2.8 Conversion of energy
[6].2.9 Devices used in energy production
[6].3 Dams and energy production
[6].3.1 Location of dams
[6].3.2 Energy production
[6].4 Nuclear energy
[6].5 Solar energy
[6].5.1 Solar collector
[6].5.2 Solar panel for energy supply
[7] Friction
[7].1 Static and dynamic friction
[7].2 Coefficient of limiting friction and its determination
[7].3 Advantages and disadvantages of friction
[7].4 Reduction of friction
[7].5 Qualitative treatment of viscosity and terminal velocity
[7].6 Stoke's law
[8] Simple Machines
[8].1 Definition of simple machines
[8].2 Types of machines
[8].3 Mechanical advantage, velocity ratio and efficiency of machines
[9] Elasticity
[9].1 Elastic limit
[9].2 Yield point
[9].3 Breaking point
[9].4 Hooke's law
[9].5 Young's modulus
[9].6 The spring balance
[9].7 Work done per unit volume
[10] Pressure
[10].1 Atmospheric Pressure
[10].1.1 Definition of atmospheric pressure
[10].1.2 Units of pressure (S.I) units (Pa)
[10].1.3 Measurement of pressure
[10].1.4 Simple mercury barometer
[10].1.4.1 Aneroid barometer
[10].1.4.2 Manometer
[10].1.5 Variation of pressure with height
[10].1.6 The use of barometer as an altimeter
[10].2 Pressure in liquids
[10].2.1 The relationship between pressure, depth and density
[10].2.2 Transmission of pressure in liquids
[10].2.3 Application
[11] Liquids At Rest
[11].1 Determination of density of solids and liquids
[11].2 Definition of relative density
[11].3 Upthrust on a body immersed in a liquid
[11].4 Archimedes' principle and law of floatation and applications
[11].4.1 Ships and hydrometers
[12] Temperature and Its Measurement
[12].1 Concept of temperature
[12].2 Thermometric properties
[12].3 Calibration of thermometers
[12].4 Temperature scales
[12].4.1 Celsius and Kelvin
[12].5 Types of thermometers
[12].6 Conversion from one scale of temperature to another
[13] Thermal Expansion
[13].1 Solids
[13].1.1 Definition and determination of linear
[13].1.2 Definition and determination of volume
[13].1.3 Definition and determination of area expansivities
[13].1.4 Effects and applications
[13].1.5 Relationship between different expansivities
[13].2 Liquids
[13].2.1 Volume expansivity
[13].2.2 Real and apparent expansivities
[13].2.3 Determination of volume expansivity
[13].2.4 Anomalous expansion of water
[14] Gas Laws
[14].1 Boyle's law (isothermal process)
[14].2 Charles' law (isobaric process)
[14].3 Pressure law (volumetric process)
[14].4 Absolute zero of temperature
[14].5 General gas equation
[14].6 Ideal gas equation
[14].7 Van der waal gas
[15] Quantity of Heat
[15].1 Heat as a form of energy
[15].2 Definition of heat capacity of solids and liquids
[15].3 Definition of specific heat capacity of solids and liquids
[15].4 Determination of heat capacity of substances
[15].5 Determination of specific heat capacity substances
[16] Change of State
[16].1 Latent heat
[16].2 Specific latent heats of fusion and vaporization
[16].3 Melting, evaporation and boiling
[16].4 The influence of pressure and of dissolved substances on boiling and melting points
[16].5 Application in appliances
[17] Vapours
[17].1 Unsaturated and saturated vapours
[17].2 Relationship between saturated vapour pressure (S.V.P) and boiling
[17].3 Determination of S.V.P by barometer tube method
[17].4 Formation of dew, mist, fog, and rain
[17].5 Study of dew point
[17].6 Study of humidity
[17].7 Hygrometry - estimation of the humidity of the atmosphere using wet and dry bulb hygrometers.
[17].8 Study of relative humidity
[18] Structure of Matter and Kinetic Theory
[18].1 Molecular nature of matter
[18].1.1 Atoms and molecules
[18].1.2 Molecular theory
[18].1.2.1 examples and applications
[18].1.2.2 Brownian motion
[18].1.2.3 Diffusion
[18].1.2.4 Surface tension
[18].1.2.5 Capillarity
[18].1.2.6 Adhesion
[18].1.2.7 Cohesion
[18].1.2.8 Angles of contact law of definite proportion
[18].2 Kinetic Theory
[18].2.1 Assumptions of the kinetic theory
[18].2.2 using the theory to explain:
[18].2.2.1 Pressure exerted by gas
[18].2.2.2 Boyle's law
[18].2.2.3 Charles' law
[18].2.2.4 Melting
[18].2.2.5 Boiling
[18].2.2.6 Vapourization
[18].2.2.7 Change in temperature
[18].2.2.8 Evaporation
[19] Heat Transfer
[19].1 conduction as mode of heat transfer
[19].2 Convection as mode of heat transfer
[19].3 Radiation as mode of heat transfer
[19].4 Temperature gradient
[19].5 Thermal conductivity
[19].6 Heat flux
[19].7 Effect of the nature of the surface on the energy radiated and absorbed by it
[19].8 The conductivities of common materials
[19].9 The thermos flask
[19].10 Land and sea breeze
[19].11 Combustion engines
[20] Waves
[20].1 Production and Propagation
[20].1.1 Wave motion
[20].1.2 Vibrating systems as source of waves
[20].1.3 Waves as mode of energy transfer
[20].1.4 Distinction between particle motion and wave motion
[20].1.5 Relationship between frequency, wavelength and wave velocity
[20].1.6 Phase difference, wave number and wave vector
[20].1.7 Progressive wave equation
[20].2 Classification
[20].2.1 Types of waves
[20].2.1.1 Mechanical and electromagnetic waves
[20].2.2 Longitudinal and transverse waves
[20].2.3 Stationary and progressive waves
[20].2.4 Waves from springs
[20].2.5 Waves from ropes
[20].2.6 Waves from stretched strings
[20].2.7 Waves from the ripple tank
[20].3 Characteristics/Properties
[20].3.1 Reflection
[20].3.2 Refraction
[20].3.3 Diffraction
[20].3.4 Plane Polarization
[20].3.5 Superposition of waves
[20].3.6 Beats
[20].3.7 Doppler effects
[21] Propagation of Sound Waves
[21].1 The necessity for a material medium
[21].2 Speed of sound in solids, liquids and air
[21].3 Reflection of sound; echoes, reverberation and their applications
[21].4 Advantages and Disadvantages of echoes and reverberations
[22] Characteristics of Sound Waves
[22].1 Noise and musical notes
[22].2 Quality, pitch, intensity and loudness and their application to musical instruments
[22].3 Simple treatment of overtones produced by vibrating strings and their columns
[22].4 Acoustic examples of resonance
[22].5 Frequency of a note emitted by air columns in closed and open pipes in relation to their lengths
[23] Light Energy
[23].1 Sources of Light
[23].1.1 Natural and artificial sources of light
[23].1.2 Luminous and non-luminous objects
[23].2 Propagation of light
[23].2.1 Speed, frequency and wavelength of light
[23].2.2 Formation of shadows and eclipse
[23].2.3 The pin-hole camera
[24] Reflection of Light at Plane and Curved Surfaces
[24].1 Laws of reflection
[24].2 Application of reflection of light
[24].3 Formation of images by plane, concave and convex mirrors and ray diagrams
[24].4 Use of the mirror formula
[24].5 Linear and angular magnification
[25] Refraction of Light Through at Plane and Curved Surfaces
[25].1 Refraction of Light Through at Plane and Curved Surfaces
[25].1.1 Explanation of refraction in terms of velocity of light in the media
[25].1.2 Laws of refraction
[25].1.3 Definition of refractive index of a medium
[25].1.4 Determination of refractive index of glass and liquid using Snell's law
[25].1.5 Real and apparent depth and lateral displacement
[25].1.6 Critical angle and total internal reflection
[25].2 Glass Prism
[25].2.1 Use of the minimum deviation formula
[25].2.2 Type of lenses - triangular, rectangular
[25].2.3 Use of lens formula
[25].2.4 Magnification
[26] Optical Instruments
[26].1 General principles of microscopes, telescopes, projectors, cameras and the human eye
[26].2 Power of a lens
[26].3 Angular magnification
[26].4 Near and far points
[26].5 Sight defects and their corrections
[27] (a) Dispersion of light and colours
[27].1 Dispersion of light and colours
[27].1.1 Dispersion of white light by a triangular prism
[27].1.2 Production of pure spectrum
[27].1.3 Colour mixing by addition and subtraction
[27].1.4 Colour of objects and colour filters
[27].1.5 Rainbow and formation
[27].2 Electromagnetic spectrum
[27].2.1 Description of sources and uses of various types of radiation
[28] Electrostatics
[28].1 Existence of positive and negative charges in matter
[28].2 Charging a body by friction, contact and induction
[28].3 Electroscope
[28].4 Coulomb's inverse square law, electric field and potential
[28].5 Electric field intensity and potential difference
[28].6 Electric discharge and lightning
[29] Capacitors
[29].1 Types and functions of capacitors
[29].2 Parallel plate capacitors
[29].3 Capacitance of a capacitor
[29].4 The relationship between capacitance, area separation of plates and medium between the plates
[29].5 Capacitors in series and parallel
[29].6 Energy stored in a capacitor
[30] Electric Cells
[30].1 Simple voltaic cell and its defects
[30].2 Daniel cell, Leclanche cell (wet and dry)
[30].3 lead-acid accumulator and Nickel-Iron (Nife) Lithium iron and Mercury cadmium
[30].4 Maintenance of cells and batteries
[30].5 Arrangement of cells
[30].6 Efficiency of a cell
[31] Current Electricity
[31].1 Electromagnetic force (emf), potential difference (p.d.), current, internal resistance of a cell and lost Volt
[31].2 Ohm's law, resistivity and conductivity
[31].3 Measurement of resistance
[31].4 Meter bridge
[31].5 Resistance in series and in parallel and their combination
[31].6 The potentiometer method of measuring emf, current and internal resistance of a cell
[31].7 Electrical networks
[32] Electrical Energy and Power
[32].1 Concepts of electrical energy and power
[32].2 Commercial unit of electric energy and power
[32].3 Electric power transmission
[32].4 Heating effects of electric current
[32].5 Electrical wiring of houses
[32].6 Use of fuses
[33] Magnets and Magnetic Fields
[33].1 Natural and artificial magnets
[33].2 Magnetic properties of soft iron and steel
[33].3 Methods of making magnets and demagnetization
[33].4 Concept of magnetic field
[33].5 Magnetic field of a permanent magnet
[33].6 Magnetic field round a straight current carrying conductor, circular wire and solenoid
[33].7 Properties of the earth's magnetic field; north and south poles, magnetic meridian and angle of dip and declination
[33].8 flux and flux density
[33].9 Variation of magnetic field intensity over the earth's surface
[33].10 Applications: earth's magnetic field in navigation and mineral exploration.
[34] Force on a Current-Carrying Conductor in a Magnetic Field
[34].1 Quantitative treatment of force between two parallel current-carrying conductors
[34].2 Force on a charge moving in a magnetic field
[34].3 The d. c. motor
[34].4 Electromagnets
[34].5 Carbon microphone
[34].6 Moving coil and moving iron instruments
[34].7 Conversion of galvanometers to ammeters and voltmeter using shunts and multipliers
[34].8 Sensitivity of a galvanometer
[35] (a) Electromagnetic Induction
[35].1 Electromagnetic Induction
[35].1.1 Faraday's laws of electromagnetic induction
[35].1.2 Factors affecting induced emf
[35].1.3 Lenz's law as an illustration of the principle of conservation of energy
[35].1.4 A.C. and D.C generators
[35].1.5 Transformers
[35].1.6 The induction coil
[35].2 Inductance
[35].2.1 Explanation of inductance
[35].2.2 Unit of inductance
[35].2.3 Energy stored in an inductor
[35].2.4 Application/uses of inductors
[35].3 Eddy Current
[35].3.1 Reduction of eddy current
[35].3.2 Applications of eddy current
[36] Simple A. C. Circuits
[36].1 Explanation of a.c. current and voltage
[36].2 Peak and r.m.s. values
[36].3 A.c. source connected to a resistor
[36].4 A.C source connected to a capacitor - capacitive reactance
[36].5 A.C source connected to an inductor inductive reactance
[36].6 Series R-L-C circuits
[36].7 Vector diagram, phase angle and power factor
[36].8 Resistance and impedance
[36].9 Effective voltage in an R-L-C circuits
[36].10 Resonance and resonance frequency
[37] Conduction of Electricity Through;
[37].1 Liquids
[37].1.1 Electrolytes and non-electrolyte
[37].1.2 Concept of electrolysis
[37].1.3 Faraday's laws of electrolysis
[37].1.4 Application of electrolysis
[37].2 Gases
[37].2.1 Discharge through gases
[37].2.2 Application of conduction of electricity through gases
[38] Elementary Modern Physics
[38].1 Models of the atom and their limitations
[38].2 Elementary structure of the atom
[38].3 Energy levels and spectra
[38].4 Thermionic and photoelectric emissions
[38].5 Einstein's equation and stopping potential
[38].6 Applications of thermionic emissions and photoelectric effects
[38].7 Simple method of production of x-rays
[38].8 Properties and applications of alpha, beta and gamma rays
[38].9 Half-life and decay constant
[38].10 Simple ideas of production of energy by fusion and fission
[38].11 Binding energy, mass defect and Einstein's Energy equation
[38].12 Wave-particle paradox (duality of matter)
[38].13 Electron diffraction
[38].14 The uncertainty principle
[39] Introductory Electronics
[39].1 Distinction between metals, semiconductors and insulators
[39].2 Intrinsic and extrinsic semiconductors
[39].2.1 N-type and p-type semiconductors
[39].3 Uses of semiconductors and diodes in rectification and transistors in amplification
[39].4 Elementary knowledge of diodes and transistors
Jamb Physics Questions - A.C. and D.C generators
Question 6:
JAMB 1991
To convert an alternating current dynamo into a direct current dynamo, the
SchoolNGR Classroom
A
Number of turns in the coil is increased
B
Strength of the field magnet is increased
C
Slip rings are replaced with a split ring commutator
D
Coil is wound on a soft iron armature
View Answer & Explanation
Question 7:
JAMB 1999
A semiconductor diode is used in rectifying alternating current into direct current mainly because it
SchoolNGR Classroom
A
Allows current to flow in either direction
B
Is non-linear
C
Offers a high input resistance
D
Allows current to flow only in one direction
View Answer & Explanation
Question 8:
JAMB 2012
A semiconductor diode is used in rectifying alternating current into direct current mainly because it
SchoolNGR Classroom
A
Allows current to flow in either direction
B
Is non-linear
C
Offers a high input resistance
D
Allows current to flow only in one direction
View Answer & Explanation
Question 9:
JAMB 2013
Capacitors are used in the induction coil to
SchoolNGR Classroom
A
Control circuits
B
Prevent distortion of electric fields
C
Prevent electric sparks
D
Dissipate energy
View Answer & Explanation
Question 10:
JAMB 2016
Which of the following does Not use magnetic effect of current to function?
SchoolNGR Classroom
A
Lead acid accumulator
B
An electric bell
C
A moving coil galvanometer
D
A telephone receiver
View Answer & Explanation
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