2023 WAEC PHYSICS OBJ;-ExamgrandComNg!!!!!
2023 WAEC PHYSICS ANSWERS;-ExamgrandComNg!!!!
The expression for the energy stored, E, in a stretched wire can be given by:
E = (1/2) * Y * A * e^2
– E represents the energy stored in the wire.
– Y is the Young’s modulus of the material, which measures its stiffness.
– A is the cross-sectional area of the wire.
– e is the extension or change in length of the wire from its original length.
The energy stored in the wire is proportional to the square of the extension and is directly influenced by the Young’s modulus and cross-sectional area.
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(i) Geostationary satellites orbit the Earth directly above the equator in a geosynchronous orbit. They remain fixed relative to a specific point on the Earth’s surface WHILE Polar satellites orbit the Earth in a polar orbit, passing over or near the North and South poles on each orbit.
(ii) Geostationary satellites have an inclination of 0 degrees, meaning their orbital plane aligns with the equatorial plane WHILE Polar satellites have a high inclination angle (usually around 90 degrees) to achieve polar orbits.
(iii) Geostationary satellites provide coverage over a large portion of the Earth’s surface (typically one-third to half) but are limited to a specific longitude range WHILE Polar satellites provide global coverage, as they pass over or near the poles on each orbit, covering the entire Earth’s surface over time.
(iv) Geostationary satellites observe the Earth from a fixed position, providing a continuous view of a specific region WHILE Polar satellites observe the Earth from a changing perspective as they orbit, resulting in different views of the Earth’s surface with each pass.
(v) Geostationary satellites primarily collect data for meteorological observations, weather forecasting, and telecommunications WHILE Polar satellites collect data for a wide range of applications, including weather monitoring, climate research, environmental monitoring, and scientific research.
(vi) Geostationary satellites are positioned at an altitude of approximately 35,786 kilometers (22,236 miles) above the Earth’s surface WHILE Polar satellites generally operate at lower altitudes, typically between 700 and 1,500 kilometers (435 to 932 miles.
(vii) Geostationary satellites provide a continuous stream of data and observations for a specific region, allowing for real-time monitoring WHILE Polar satellites have a lower data refresh rate since they pass over a given area less frequently. However, they provide a broader coverage over time.
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Diffusion refers to the process by which fluid molecules or particles move from an area of higher concentration to an area of lower concentration. This movement occurs due to the random motion of molecules, as described by the kinetic theory.
Diffusion is the spontaneous movement of fluid molecules from an area of high concentration to an area of low concentration. According to the kinetic theory, molecules possess kinetic energy and random motion, leading to collisions and subsequent redistribution, resulting in the even distribution of molecules throughout the fluid.
Diffusion is the process by which fluid molecules move from a higher concentration area to a lower concentration area. According to the kinetic theory, fluid molecules are in constant motion, colliding with each other and their surroundings. These collisions cause them to move randomly, leading to the gradual spreading and intermingling of molecules throughout the fluid.
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5. (a) The kinetic theory states that all matter is made up of tiny particles (atoms or molecules) that are in constant motion. Diffusion is the process by which these particles move from an area of high concentration to an area of low concentration, due to their random motion. This occurs because the particles collide with each other and bounce off in different directions, spreading out over time. The rate of diffusion depends on factors such as temperature, pressure, and the size and shape of the particles. In general, diffusion is faster at higher temperatures and lower pressures, and for smaller particles that can move more easily through a medium.
Wave: Diffraction of light through a narrow slit or around an obstacle is a phenomenon that demonstrates that light behaves as a wave. This is because the diffraction pattern of light shows interference fringes, which are characteristic of wave interference.
Particle: The photoelectric effect is a phenomenon that demonstrates that light behaves as a particle. This is because the photoelectric effect involves the emission of electrons from a metal surface when it is illuminated by light. The energy of the emitted electrons is proportional to the frequency of the light, which is consistent with the idea that light is made up of particles, or photons, with discrete energy levels.
(a) One difference between an intrinsic and an extrinsic semiconductor is that intrinsic semiconductors are pure materials (such as silicon or germanium) with no intentional impurities added, while extrinsic semiconductors have small amounts of impurities (dopants) intentionally added to alter their electrical properties.
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Fiber optics refers to a technology that utilizes thin, flexible strands of glass or plastic called optical fibers to transmit information in the form of light pulses.
Fiber optics refers to the technology that uses thin strands of glass or plastic fibers to transmit data and information in the form of light signals
Fiber optics is a method of transmitting light signals through optical fibers for the purpose of communication or data transmission.
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(i) Optical fibers have a much higher bandwidth compared to copper cables.
(ii) Optical fibers can transmit signals over much longer distances without experiencing significant signal degradation unlike copper cables which are limited in their transmission.
(iii) Optical fibers are immune to Electromagnetic Interference while copper cables are susceptible to interference
(iv) Optical fibers offer improved security for data transmission whereas copper cables are vulnerable to eavesdropping or unauthorized access
(v) Optical fibers are much thinner and lighter than copper cables, making them easier to install and handle.
(b) Two reasons why optical fibers are preferred to copper cables in telecommunications are:
– Optical fibers have much higher bandwidth and can transmit data at much higher speeds over longer distances without signal degradation.
– Optical fibers are immune to electromagnetic interference and do not generate electromagnetic fields, making them more secure and reliable for transmitting sensitive information.
(i) Pivot: A pivot is a point or axis around which a lever or other mechanical device rotates or pivots.
(ii) Load: A load is the object or weight that is being moved or lifted by a simple machine.
(iii) Efficiency: Efficiency is the measure of how much work or energy is input into a machine compared to how much useful work or energy is output, expressed as a percentage.
Parabolic mirrors are suitable for use in headlamps of vehicles because they can focus light in a specific direction, are efficient at reflecting light, and are durable.
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