# Waec Physic questions and answers 2023

Here is the Waec Physic questions and answers 2023.

*PHYSICS OBJ:*

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(4). |TABULATE|
Geo-stationary satellites||
Polar satellites
(i) Orbital
Revolve in equatorial orbits and complete one circle of the earth in 24 hours.
Revolve in polar orbits of the earth and take less time to complete one circle of earth.
(ii) Distance from the Earth surface
Placed at a height of 36000km from the Earth surface.
Placed at a height of 500800km from Earth surface.
(iii) Uses
Uses as communication satellites.
Remote sensifig, weather, science and environment related studies.
4.
– Orbit: Geostationary satellites orbit at an altitude of approximately 36,000 kilometers above the equator, while polar satellites orbit at a lower altitude and pass over the poles.
– Coverage: Geostationary satellites provide continuous coverage of a specific region on Earth, while polar satellites provide global coverage but only observe a particular area for a short amount of time during each orbit.
– Applications: Geostationary satellites are commonly used for communication, weather forecasting, and navigation, while polar satellites are primarily used for Earth observation, such as monitoring weather patterns, ocean currents, and land use.

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.

5(b)
(i) One phenomenon that demonstrates that light behaves as a wave is interference, where two or more waves can combine to form a new wave with a different amplitude and wavelength.
(ii) One phenomenon that demonstrates that light behaves as a particle is the photoelectric effect, where light can knock electrons off a metal surface, indicating that light has energy in discrete packets called photons.

6. (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.

(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.

9. (a)
(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.
No 1

To use dimensional analysis to determine the values of x, y and z, let’s first look at the dimensions of each variable:

F = force
v = velocity
p = density
A = surface area

Using the dimensions of these variables, we can write:

F = [M L T^-2]
v = [L T^-1]
p = [M L^-3]
A = [L^2]

Substituting these dimensions into the given equation, we get:

[M L T^-2] = k [M L^-3] ^x [L T^-1]^y [L^2]^z

Simplifying the right-hand side, we get:

[M L T^-2] = k [M^x L^(-3x+2y+2z) T^(-y)]

Equating the dimensions on both sides, we get:

For mass: 1 = x
For length: 1 = -3x + 2y + 2z
For time: -2 = -y

Solving for x, y, and z, we get:

x = 1
y = 2
z = 0

Therefore, the values of x, y, and z are 1, 2, and 0 respectively.
8. (a) Simple harmonic motion is periodic because it repeats itself after a fixed time interval, known as the period, and the motion is governed by a restoring force that brings the system back to its equilibrium position.

(b) Two factors that affect the period of oscillation of a simple pendulum are:

– Length of the pendulum: The longer the pendulum, the longer the period of oscillation.
– Acceleration due to gravity: The higher the acceleration due to gravity, the shorter the period of oscillation.

9. (c) Two differences between absolute zero temperature and ice point are:

– Absolute zero temperature is the lowest possible temperature, at which all substances have zero thermal energy and all molecular motion ceases, while ice point is the temperature at which water freezes into ice at standard atmospheric pressure.
– Absolute zero temperature is an absolute scale with a fixed reference point, while ice point is a relative scale based on the freezing point of water.

11. The electric potential at a point in an electric field is defined as the amount of work done per unit charge in bringing a test charge from infinity to that point in the electric field.

(ii) The method of induction charges an uncharged body by bringing a charged object near it, causing a redistribution of charges in the uncharged body without direct contact. The method of contact charges an uncharged body by direct contact with a charged object, allowing electrons to transfer between them until they reach equilibrium.

(7a)
(PICK ANY ONE)
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.

OR

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

OR

Fiber optics is a method of transmitting light signals through optical fibers for the purpose of communication or data transmission.

(7b)
(PICK ANY TWO)
(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.

Good luck

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