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 2266–2280 of 5315 verified questions
Sort by:
Physics
UTME / JAMB 2008
Equilibrium of Forces, Moments & Flotation
Diagram
Solution
The diagram above shows a plank RS pivoted its center of gravity O and is in equilibrium with the weight P and Q. If a weight 2P is added to P the plank will be in equilibrium again by?
Attached Figure / Diagram
A
moving Q nearer to O
B
moving P nearer to O
C
addding a weight Q to Q
D
moving P further away from O
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
If 2P is added P, the beam will bend at R side. So to keep it in equilibrium. P should be moved nearer to 0
Source: WAEC / JAMB / NECO Classroom Archive (Record #14486)
Physics
UTME / JAMB 2008
Circular Motion, Gravitation & Simple Harmonic Motion
Solution
What is the frequency of vibration if the balance wheel of a wrist watch makes 90 revolutions in 25 s?
A
0.01 Hz
B
0.04 Hz
C
2.27 Hz
D
3.60 Hz
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
Frequency = (No. of revolutions)/ Time = (90)/25 = 3.6 Hz
Source: WAEC / JAMB / NECO Classroom Archive (Record #14020)
Physics
UTME / JAMB 2008
Elasticity, Density, Pressure & Fluids
Solution
Counting of currency notes with moist fingers is based on the principles of?
A
diffusion
B
cohesion
C
adhesion
D
viscosity
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
since currency and finger contain unlike molecules, the force involved is adhesion
Source: WAEC / JAMB / NECO Classroom Archive (Record #14024)
Physics
UTME / JAMB 2008
Elasticity, Density, Pressure & Fluids
Solution
A spring of force constant 500 Nm\(^{-1}\) is compressed such that its length shortens by 5cm. The energy stored in the spring is?
A
0.625 J
B
6.250 J
C
62.500 J
D
625.000 J
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
Energy stored in a spring = (1)/2 K e2 = (1)/2 x 500(0.05)2 = 0.625J
Source: WAEC / JAMB / NECO Classroom Archive (Record #14028)
Physics
UTME / JAMB 2008
Scalars, Vectors & Relative Motion
Solution
The resultant of two forces 12N and 5N is 13N. What is the angle between the two forces?
A
0o
B
45o
C
90o
D
180o
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
R\(^2\) = P\(^2\) + Q\(^2\) = 12\(^2\) + 5\(^2\)
= 144 + 25 = 169
∴R = \(\sqrt{169}\) = 13N
∴ the angle between the forces is 90º
Source: WAEC / JAMB / NECO Classroom Archive (Record #14483)
Physics
UTME / JAMB 2008
Temperature, Thermometry & Thermal Expansion
Solution
When cold water is poured on a can containing hot water, the can collapses because the?
A
steam condeses and occupies the partial vacuum in the can
B
external air pressure counter balances the pressure within the can
C
steam expands to occupy the vacuum remaining in the can
D
external pressure becomes greater than the pressure within the can.
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
Cold water reduces the temperature of the hot water inside the can causing the contraction of the hot water. This reduces the pressure inside the can and the can collapses due to the external greater expression.
Source: WAEC / JAMB / NECO Classroom Archive (Record #14032)
Physics
UTME / JAMB 2008
Temperature, Thermometry & Thermal Expansion
Solution
The thermometric properties of a thermocouple is the change in?
A
equivalent resistance
B
electromotive force
C
colour
D
pressure
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
Temperature difference between hot and cold junctions of thermocouple is proportional to the emf. generated
Source: WAEC / JAMB / NECO Classroom Archive (Record #14039)
Physics
UTME / JAMB 2008
Temperature, Thermometry & Thermal Expansion
Solution
During summer, the balance wheel of a clock expands.what effect does this have on the accuracy of the clock?
A
the clock gians time
B
the accuracy of the clock is not affected
C
the clock losses time
D
the clock stops working
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
The elastic potential energy of the balance wheel reduces as the wheel expands, therefore the clock will loose time.
Source: WAEC / JAMB / NECO Classroom Archive (Record #14040)
Physics
UTME / JAMB 2008
Temperature, Thermometry & Thermal Expansion
Solution
A sealed flask contains 600cm3 of air at 27°C and is heated to 35°C at constant pressure. The new volume is?
A
508 cm3
B
516 cm3
C
608 cm3
D
616 cm3
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
V1 = 600cm3, T1 = 27 = 273 = 300k
T2 = 35 + 273 = 308K, V2 = ?
(V)1/T1
= (V)2/T2 = V2
= (V)1/T1 x X T2
= (600 X 308)/300 = 616 cm3
Source: WAEC / JAMB / NECO Classroom Archive (Record #14041)
Physics
UTME / JAMB 2008
Temperature, Thermometry & Thermal Expansion
Solution
If the partial pressure of water vapour at 27°C is 18 mm Hg and the saturated vapour pressure of the atmosphere at the same temperature is 24 mm Hg, the relative humidity at this temperature is?
A
25%
B
33%
C
75%
D
82%
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
Relative
Humidity = (S.V.P. of water at dew point)/S.V.P of water at air temperature =(18)/24 x 100% = 75%
Source: WAEC / JAMB / NECO Classroom Archive (Record #14043)
Physics
UTME / JAMB 2008
Gas Laws & Heat Transfer
Diagram
Solution
The diagram above is the heating curve for a solid, QR is the?
Attached Figure / Diagram
A
melting region
B
boiling region
C
sublimation region
D
evaporating process
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
At melting point there is no change temperature
Source: WAEC / JAMB / NECO Classroom Archive (Record #14488)
Physics
UTME / JAMB 2008
Calorimetry, Latent Heat & Change of State
Solution
A block of aluminum is heated electrically by a 25 W heater. if the temperature rises by 10°C in 5 minutes, the heat capacity of the aluminum is?
A
850 JK-1
B
750 JK-1
C
650 JK-1
D
500 JK-1
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
Heat supplied = Heat gained
P x t = C ∆ Ø
(25 x 5 x 60)/10 = 750 JK-1
Source: WAEC / JAMB / NECO Classroom Archive (Record #14042)
Physics
UTME / JAMB 2008
Magnetism, Electromagnetism & AC Circuits
Solution
A step-down transformer has a power output of 50 W and efficiency of 80%. if the mains supply voltage is 200 v, calculate the primary current of the transformer.
A
0.31 A
B
3.20 A
C
3.40 A
D
5.00 A
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
To find the primary current of the step-down transformer, we follow these steps:
1. Calculate the Power Input:
The efficiency (\( \eta \)) of the transformer is given by:
\(\eta = \frac{\text{Power Output}}{\text{Power Input}} \times 100\)
Rearranging gives:
\(\text{Power Input} = \frac{\text{Power Output}}{\eta}\)
Given:
- Power Output = 50 W
- Efficiency = 80\% = 0.80
Thus,
\(\text{Power Input} = \frac{50 \, \text{W}}{0.80} = 62.5 \, \text{W}\)
2. Calculate the Primary Current:
The power input can also be expressed in terms of voltage and current:
\(\text{Power Input} = V_p \times I_p\)
Where:
- \( V_p \) = primary voltage (given as 200 V)
- \( I_p \) = primary current (what we want to find)
Rearranging gives:
\( I_p = \frac{\text{Power Input}}{V_p}\)
Now substituting the values:
\(I_p = \frac{62.5 \, \text{W}}{200 \, \text{V}} = 0.3125 \, \text{A}\)
Thus, the primary current of the transformer is: 0.3125A
Source: WAEC / JAMB / NECO Classroom Archive (Record #14078)
Physics
UTME / JAMB 2008
Magnetism, Electromagnetism & AC Circuits
Diagram
Solution
Given the inductor of inductance 5mH, 10mH and 20mH connected in series, the effective inductance is
Attached Figure / Diagram
A
0.35mH
B
3.50mH
C
2.90mH
D
35.0mH
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
Left = L1 + L2 + L3
= 5mH + 10mH + 20mH = 35mH
Source: WAEC / JAMB / NECO Classroom Archive (Record #14492)
Physics
WAEC / WASSCE 2008
Electrostatics & Capacitors
Solution
Two bodies each carrying a charge of 2.00 x 10-10C are 5cm apart. Calculate the magnitude of the force between the charges.[\(\frac{1}{4\pi \mathit{E}_o} = 9.00 \times 10^9 Nm^2C{-2}\)]
A
1.44 x 10-7N
B
7.20 x 10-9N
C
7.20 x 10-11N
D
1.44 x 1011N
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
f = \(\frac{1}{4 \pi \mathit{E}_o} \times \frac{Q^2}{r^2} = \frac{9 \times 10^9(2 \times 10^{-2})^2}{(0.05)^2}\)
= 1.44 x 10-2N
Source: WAEC / JAMB / NECO Classroom Archive (Record #35082)