Waec 2023 SS3 Physics Amswer / Waec 2023 physics Answer



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INSTRUCTIONS: Answer Six(6) Questions From This Part. Question 1 and Any other Five (5).

(i) Education
(ii) Pipeline inspection

Draw the diagram
IMG 20211209 WA0368

U = 39cm
V = 720cm
f = ?
Using lens formula
1/f = 1/v + 1/u
1/f = (1/720) + (1/30)
1/f = (1 + 30/720)
1/f = 25/720
f = 720/25
f = 28.8cm

(i) Planets revolving around the sun
(ii) Satellites orbiting around planets

Mass is the measure of the amount of matter present a body. While weight refers to the measure of the amount of force that acts on mass because of the pull of gravity.

M = 40g = 0.04kg
K = 0.5Nm-¹
Period T=?
T = 2π √m/k
T = 2π √0.04/0.5
T = 1.776seconds

Frequency = 1/T
F = 1/1.776
F = 0.563Hz

K.E of object = Potential energy of stone
1/2MV² = Mgh
1/2M x (10)² = 5 x 10 x 20
50M = 50×20
M = 20kg
Mass of object is 20kg

(i) Coal is potentially radioactive:
Other than abundant levels of carbon dioxide, coal also produces sufficient levels of outward radiation. These radiations are carcinogenic in that they cause cancer and cell mutations. The use of safety gear is one way of achieving this desirable end.
(ii) Coal destroys natural habitats:
In extracting coal for heating and industrial use, the habitats of plants and animals inevitably get destroyed. The situation is compounded by fire outbreaks that are more likely to arise in extracting the coal. This may pose extreme damages to the nearby infrastructure.

(i) Elastic collision is whereby two colliding objects do not stick together; they bounce back without undergoing any deformation or heat generation.
(ii) In elastic collision, the momentum and total kinetic energy before and after collision is same.
(iii) The forces involved during elastic collision are conservative.
(iv) In elastic collision, mechanical energy is not transformed into other energies such as sound energy or thermal energy.

(i) Inelastic collision is a kind of collision whereby the two colliding objects stick together and move with the same post-collision speed.
(ii) In inelastic collision, the momentum and total kinetic energy before and after collision is not same.
(iii) The forces involved during inelastic collision are non-conservative.
(iv) In inelastic collision, mechanical energy is transformed into other forms of energy such as sound energy and thermal energy.

(i) Violent light
(ii) Red light

n = Sin i/Sin r
1.5 = sin 30°/sin r
1.5 = 0.5/sin r
r = Sin-¹(0.333)
r = 19.5°

(i) Extraction and Refining of Metals:
In the process of refining of metals the impure metal extracted from its ore is made anode, the salt of the metal is made electrolyte. Pure metal deposits on the cathode.
(ii) Production of chemicals:
During the process of electrolysis of brine, chlorine is given off. at one pole at anode and hydrogen at the other at cathode leaving caustic soda in the cell.

A conductor is described as a material that permits electrons to flow freely and easily from one particular to another in one or more than one directions. While an Insulator is a material that does not permit electrons to flow freely.

Answer Any Four Questions From This Part

The two rods had different temperatures because they have different specific heat capacities.

Screenshot 20211209 162248

R = MgCos30°
= 150 x Cos30°
= 130N

U = F/R
= 150/130
= 1.154

Accommodation is the ability of the eye to alter or adjust the focal length of its lens so as to form clear images of objects at different distances on its retina

A convex mirror has a wide range of view

Draw the Diagram
IMG 20211209 WA0066

Comparing; y= 5sin(500πt – 2.5x)
With y = Asin(2πft – 2πx/λ)
(i) 2πf = 500π
2f = 500
f = 500/2 = 250Hz
(ii) 2π/λ = 2.5
λ = 2π/2.5
λ = 2(3.14)/2.5 = 2.512m

Newton’s law of gravitation, states that any particle of matter in the universe attracts any other with a force varying directly as the product of the masses and inversely as the square of the distance between them.

Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms While Reactance only occurs during a change of current in inductors and capacitors. Reactance depends on the frequency of the alternating current through an inductor or capacitor.

Screenshot 20211209 161803

Total voltage = 4(10) + 2(15) + 1(65)
= 135
Energy consumed = Power x time
= 135 x 3
= 405wh
= 0.405kwh

Cost = ₦35 x 0.405
= ₦12.96

Artificial radioactivity is the process of using radiation to make a previously stable material radioactive. It is produced in a substance by bombardment with high-speed particles such as protons or neutrons.

Nuclear reactors are used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions.

Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy.

(i) By heating
(ii) By addition of soap or detergent

f° = 5.0 x 10^14Hz
Work function w° = hf°
= 6.63×10^-34 x 5.0×10^14
= 33.15×10^-19J
= 0.55ev

Energy = wf – w°
= (6.63×10^-34 x 6.0×10^15) – (3.315×10^-19)
= 36.465×10^-19J
= 22.76ev


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