Question Library
Browse, filter, and study verified past examination questions with step-by-step mathematical reasoning.
Searching 18,000+ Questions...
Sifting topics, KaTeX formulas & verified solutions
Showing 1606–1620 of 13612 verified questions
Sort by:
Physics
WAEC / WASSCE 2021
Energy and Power
Solution
Electric motor primarily converts?
A
electrical energy to chemical energy.
B
kinetic energy to potential energy
C
electrical energy to mechanical energy
D
electrical energy to heat energy.
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
An electric motor is an electrical machine that converts electrical energy into mechanical energy.
Source: WAEC / JAMB / NECO Classroom Archive (Record #61880)
Physics
WAEC / WASSCE 2021
Energy and Power
Diagram
Solution
In the diagram above, a bulb is lit by drawing 2.0A from 440V a.c. source. Calculate the cost of keeping the bulb on for two days at $0.40 per kilowatt-hour.
Attached Figure / Diagram
A
$16.90
B
$84.48
C
$1690.00
D
$8.48
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
Power[p] = IV → 2 * 440 = 880Watt
Energy = p * t = 880 * 48hrs
= 42240 or 42.24kwh
But 1 kwh cost $0.40
∴ 42.24kwh costs 42.24 x 0.40
= 16.896 or $16.90
Source: WAEC / JAMB / NECO Classroom Archive (Record #61984)
Physics
WAEC / WASSCE 2021
Simple Ac Circuit
The inductive reactance in a circuit of frequency 100Hz is 1ohms. Calculate the inductance of the inductor[π = 3.14]
A
2.00 x 10\(_{-3}\)H
B
1.59 x 10\(_{-3}\)H
C
1.09 x 10\(_{-3}\)H
D
6.28x 10\(_{-3}\)H
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: WAEC / JAMB / NECO Classroom Archive (Record #61902)
Physics
WAEC / WASSCE 2021
Simple Ac Circuit
Diagram
Solution
The diagram above is an illustration of an a.c. circuit.Calculate the reactance of the capacitor.
Attached Figure / Diagram
A
2016Ω
B
2000Ω
C
200Ω
D
4000Ω
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
Capacitive reactance, X\(_C\) = \(\frac{1}{2\piFC}\) → \(\frac{1}{2\pi * 500/\pi * 5 * 10^{-6}}\)
= \(\frac{1}{0.005}\) → 200\Omega
Source: WAEC / JAMB / NECO Classroom Archive (Record #61913)
Physics
WAEC / WASSCE 2021
Structure of the Nucleus
Solution
An atom that emits an a-particle?
A
may become a different element.
B
becomes a different isotope of the element.
C
daughter with increased mass.
D
becomes a daughter of a different element always.
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
Alpha decay or \alpha-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and
thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.
Source: WAEC / JAMB / NECO Classroom Archive (Record #61904)
Physics
WAEC / WASSCE 2021
Structure of the Nucleus
Solution
Which of the following scientist suggested that moving particles exhibit wave properties?
A
Isaac Newton
B
Ernest Rutherford
C
Louis de Broglie
D
J.J. Thompson
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
In 1924 Louis de Broglie introduced the idea that particles, such as electrons, could be described not only as particles but also as waves.
Source: WAEC / JAMB / NECO Classroom Archive (Record #62317)
Physics
WAEC / WASSCE 2021
Waves
The distance between a node and its adjacent antinode of a transverse wave is equal to?
A
half of the wavelength.
B
the wavelength.
C
thrice the wavelength.
D
quarter of the wavelength.
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: WAEC / JAMB / NECO Classroom Archive (Record #61882)
Physics
WAEC / WASSCE 2021
Waves
Which of the following statements is not a characteristic of a plane progressive wave?
A
Energy travels out through the medium
B
Neighboring points along the profile possess different amplitudes
C
Neighboring points along the profile possess the same amplitude
D
Neighboring particles vibrate with different phase
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: WAEC / JAMB / NECO Classroom Archive (Record #62309)
Chemistry
WAEC / WASSCE 2021
Basic Chemistry
Solution
The Bohr model of the atom proposed the existence of?
A
the nucleus
B
electron shells
C
nucleons
D
neutrons
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Bohr Model is a planetary model in which the negatively charged electrons orbit a small, positively charged nucleus similar to the planets .
Source: WAEC / JAMB / NECO Classroom Archive (Record #62092)
Chemistry
WAEC / WASSCE 2021
Acids, Bases, and Salts
Solution
The basic property of salts used as drying agents is by?
A
efforescence
B
high melting point
C
hygroscopy
D
low solubility
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Hygroscopic substances are used to keep products dry or to remove water from an area. They are commonly used in desiccators
Some common examples of hygroscopic substances include: Sodium chloride. Zinc chloride. Calcium chloride
Source: WAEC / JAMB / NECO Classroom Archive (Record #61979)
Chemistry
WAEC / WASSCE 2021
Shapes of Molecules and Solids
Solution
Which of the following pairs of molecules form hydrogen bonds?
A
\(C_2\)\(H_5\)OH and C\(H_3\)OH
B
C\(H_3\)OH and \(H_2\)
C
\(H_2\)S and C\(H_4\)
D
N\(H_3\) and S\(O_2\)
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
In alcohols the hydrogen bond is formed due to the covalent bonds between one oxygen atom and one hydrogen atom in the hydroxyl group (O—H).
Source: WAEC / JAMB / NECO Classroom Archive (Record #62123)
Chemistry
WAEC / WASSCE 2021
Shapes of Molecules and Solids
Solution
A coordinate covalent bond could be formed between?
A
N\(H_3\) and PC\(l_3\)
B
BC\(l_3\) and AlC\(l_3\)
C
BC\(l_3\) and N\(H_3\)
D
H\(^{+}\) and AlC\(l_3\)
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
A coordinate covalent bond, also known as a dative bond, dipolar bond, or coordinate bond is a kind of two-center, two-electron covalent bond in which the two electrons derive from the same atom.
Source: WAEC / JAMB / NECO Classroom Archive (Record #62131)
Chemistry
WAEC / WASSCE 2021
Oxygen Oxides Ozone
Solution
Which of the following oxide causes acid rain?
A
CO
B
NO
C
\(H_2\)\(O_2\)
D
N\(O_2\)
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the atmosphere and transported by wind and air currents.
The SO2 and NOX react with water, oxygen and other chemicals to form sulfuric and nitric acids.
Source: WAEC / JAMB / NECO Classroom Archive (Record #61873)
Chemistry
WAEC / WASSCE 2021
Organic Chemistry
Diagram
Solution
The alkanol represented by the structure above is
Attached Figure / Diagram
A
primary and dihydric
B
secondary and monohydric
C
tertiary and dihydric
D
secondary and dihydric
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
It is primary alcohol because it has only one alkyl group and dihydric because it has two hydroxyl groups
Source: WAEC / JAMB / NECO Classroom Archive (Record #61890)
Physics
WAEC / WASSCE 2021
Mechanics and Properties of Matter
Solution
Which of the following quantities is not an example of force?
A
Mass
B
Tension
C
Weight
D
Friction
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
Mass is a measure of how much matter is in an object.
Source: Myschool Past Questions Archive (Record #61868)