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Physics
UTME / JAMB 1985
Current Electricity & Electric Circuits
Solution
A force of 100N stretches an elastic string to a total length of 20cm. If an additional force of 100N stretches the string 5cm further, Find the natural length of the string
A
15cm
B
12cm
C
10cm
D
8cm
E
5cm
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
Using, f1 = f2
e1 = 20 - L ; e2 = 5cm
\(\frac{f_1}{e_1}\) = \(\frac{f_2}{e_2}\)
\(\frac{100}{20 - L}\) = \(\frac{100}{5}\)
hence, L = 15cm
Source: Myschool Past Questions Archive (Record #28567)
Physics
UTME / JAMB 1985
Work, Energy, Power & Simple Machines
Solution
The areas of the effort and load pistons of a hydraulic press are 0.5m2 and 5m2 respectively. If a force F1 of 100N is applied on the effort piston, the force F2 on the load is
A
10N
B
100N
C
500N
D
1000N
E
5000N
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
\(\frac{load}{area}\) = \(\frac{effort}{area}\)
\(\frac{load}{5}\) = \(\frac{100}{0.5}\)
load = 1000N
Source: Myschool Past Questions Archive (Record #28572)
Physics
UTME / JAMB 1985
Current Electricity & Electric Circuits
Solution
A metal cube of volume 103mm3 is lowered into a measuring cylinder containing water. If the internal cross-sectional area of the cylinder is 1.5 x 102mm2, by how much does the water level rise in the cylinder?
A
6.67 x 100mm
B
8.50 x 102mm
C
1.15 x 103mm
D
2.50 x 103mm
E
1.50 x 105mm
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
Height = \(\frac{volume}{area}\)
= Height = \(\frac{10^3}{1.5 \times 10^2}\)
= 6.67mm
Source: Myschool Past Questions Archive (Record #28573)
Physics
UTME / JAMB 1985
Equilibrium of Forces, Moments & Flotation
Solution
A uniform cylindrical block of wood floats in water with one-third of its height above the water level, in a liquid of relative density 0.8, what fraction of its height will be above the liquid level?
A
\(\frac{1}{6}\)
B
\(\frac{1}{5}\)
C
\(\frac{1}{3}\)
D
\(\frac{4}{5}\)
E
\(\frac{5}{6}\)
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
A floating body displaces its own weight of the liquid in which it floats.
i.e mass of block = mass of water = mass of liquid
let the fraction of the volume of the block in liquid be q
\(\frac{2}{3}\)V x 1 = Vq X 0.8
q = \(\frac{2V}{2.4V}\) = \(\frac{5}{6}\)
Therefore, the fraction of the height above the liquid level is (1–\(\frac{5}{6}\)) = \(\frac{1}{6}\).
Source: Myschool Past Questions Archive (Record #28574)
Physics
UTME / JAMB 1985
Elasticity, Density, Pressure & Fluids
Solution
Normal atmospheric pressure at sea-level is 105Nm-2 and the acceleration due to gravity is approximately 10ms-1. If the atmosphere has a uniform density of 1kgm-3, its height is
A
100m
B
1000m
C
10 000m
D
100 000m
E
1000 000m
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
pressure = h x g x e
105 = 10 x h x 1
h = 104
Source: Myschool Past Questions Archive (Record #28728)
Physics
UTME / JAMB 1985
Equilibrium of Forces, Moments & Flotation
Solution
In the Fig above, MN is a light uniform meter rule pivoted at O, the 80cm mark. A load of mass 3.00kg is suspended on the meter rule at L, the 10cm mark. If the rule is kept in equilibrium by a string RP, fixed at P and attached to the rule at R, the 20cm mark, then the Tension T on the string is?
A
3.0N
B
3.4N
C
3.5N
D
6.0N
E
7.0N
medium Difficulty
Verified Correct Answer: Option E
Physical Principles & Numerical Solution
T * sin30 \times 60 = 3 * 70
: T = 7N
Source: Official Exam / Past Question Archive
Physics
UTME / JAMB 1985
Current Electricity & Electric Circuits
Diagram
Solution
In the Fig above, Current I passes through the combination, if the power dissipated in the 5 ohm resistor is 40W, then the power dissipated in the 10 ohm resistor is
Attached Figure / Diagram
A
10W
B
20W
C
40W
D
80W
E
100W
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
Since the resistors are in parallel, the p.d across them is the same,
P = VI but I = \(\frac{ V}{R}\)
P = \(\frac{ V^2}{R}\) = power dissipated by 5\Omega resistor,
40 = \(\frac{ V^2}{5}\)
\(V^2\) = 200V.
Power dissipated by the 10\Omega resistor,
P = \(\frac{ V^2}{R}\) = \(\frac{200}{10}\)
P = 20W.
Source: Myschool Past Questions Archive (Record #41647)
Physics
UTME / JAMB 1985
Current Electricity & Electric Circuits
Diagram
The graph in the fig above describes the motion of a particle. the acceleration of the particle during the motion is
Attached Figure / Diagram
A
0.00ms-2
B
0.25ms-2
C
4.00ms-2
D
8.00ms-2
E
10.00ms-2
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #41648)
Physics
UTME / JAMB 1985
Equilibrium of Forces, Moments & Flotation
Diagram
Solution
In the Fig above, MN is a light uniform meter rule pivoted at O, the 80cm mark. A load of mass 3.00kg is suspended on the meter rule at L, the 10cm mark. If the rule is kept in equilibrium by a string RP, fixed at P and attached to the rule at R, the 20cm mark, then the Tension T on the string is?
Attached Figure / Diagram
A
3.0N
B
3.4N
C
3.5N
D
6.0N
E
7.0N
medium Difficulty
Verified Correct Answer: Option E
Physical Principles & Numerical Solution
T * sin30 \times 60 = 3 * 70
: T = 7N
Source: Myschool Past Questions Archive (Record #41649)
Chemistry
UTME / JAMB 1985
Stoichiometry, Mole Concept & Volumetric Analysis
X + Y = Z is an equilibrium reaction. The addition of a catalyst?
A
increase the amount of Z produced in a given time
B
increases the rate of change in concentrations of X, Y and Z
C
increases the rate of disapearance of X and Y
D
increases the rate of the forward reaction
E
decreases the amounts of X and Y left after the attainment of equilibrium
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #14109)
Chemistry
UTME / JAMB 1985
Oxidation, Reduction & Redox Reactions
Solution
What is the formula of sodium gallate if gallium (Ga)shows an oxidation number of + 3?
A
NaGaO3
B
Na2Ga(OH)3
C
NaGa(OH)3
D
NaGa(OH)4
E
NaGaO
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
To determine the formula of sodium gallate with gallium having an oxidation state of +3, we need to consider the charges of the ions involved.
Sodium Ion (Na+) Charge: +1
Gallate Ion (GaO\(_3\)\(^{3-}\) or Ga(OH)\(_4\)\(^-\)
- Gallium (Ga) has an oxidation state of +3.
- Oxygen (O) has an oxidation state of -2.
- The formula for the gallate ion would be GaO\(_3\)\(^{3-}\) to balance the +3 charge on Ga with three -2 charges on O, resulting in a net -3 charge for the ion (3*(-2) + 3 = -3).
Option D: NaGa(OH)\(_4\) seems plausible because:
1. Ga (+3) + 4OH (-1 each) → Ga(OH)\(_4\)\(^-\) (net charge -1)
2. Na\(^+\) balances the charge, making NaGa(OH)\(_4\) a valid formula.
The most fitting formula for sodium gallate with gallium in the +3 oxidation state is option D, NaGa(OH)\(_4\).
Source: Myschool Past Questions Archive (Record #14110)
Chemistry
UTME / JAMB 1985
Air & Environmental Chemistry
If the ONLY pollutants found in the atmosphere over a city are oxides of nitrogen, suspended lead compounds. carbon monoxide and high levels of methane, the probable source(s) of the pollution must be?
A
automobile exhaust and biological decomposition
B
combustion of coal and automobile exhaust
C
biological decomposition only
D
combustion of coal, automobile exhaust and biological decomposition
E
combustion of coal and biological decomposition
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #14111)
Chemistry
UTME / JAMB 1985
Stoichiometry, Mole Concept & Volumetric Analysis
A certain industrial process is represented by the chemical equation 2A(g) + B(g) \(\to\) C(g) + 3D(g) \(\Delta\)H = X kJmol-1. Which of the following conditions will favour the yield of the products?
A
increase in temperature, decrease in pressure
B
increase in temperature, increase in pressure
C
decrease in temperature,increase in pressure
D
decrease in temperature, decrease in pressure
E
constant in temperature, increase in pressure
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #14113)
Chemistry
UTME / JAMB 1985
Oxidation, Reduction & Redox Reactions
2MnO-4 + 10Cl- + 16H+ → 2Mn2+ + 5Cl2 + 8H2O. Which of the substances serves as an oxidizing agent?
A
Mn2+
B
Cl-
C
H2O
D
MnO-4
E
Cl2
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #14114)
Chemistry
UTME / JAMB 1985
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following metals will displace iron from a solution of iron(ll)tetraoxosulphate(lV)?
A
Copper
B
Mercury
C
Silver
D
Zinc
E
Gold
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #14115)