The momentum of a car moving at a constant speed in a circular track

can be zero depending on its position in the track

can be both positive and negative

can be zero depending on its position in the track

The mass of a nucleus is the

total number of its proton and neutrons

total number of its protons and electrons

A body was slightly displaced from its equilibrium position. Which one of the following is a condition for its stable equilibrium

an increase in the potential energy of the body

an increase in the kinetic energy of the body

an increase in the potential energy of the body

an increase in the height of the body

Gases conduct electricity under

normal pressure and low voltage

Aluminium is sometimes used as the leaf of an electroscope because it

can be converted into thin sheets

- angle of dip is zero at the magnetic equator - angle of variation is the same as angle of declination.

horizontal component at the Earth's field is zero

The pin-hole camera produces a less sharply defined image when the

screen is further from the pin-hole

object is further from the pin-hole

An alternating current can induce voltage because it has

weaker magnetic field than direct current

JAMB UTME - Physics - 2019 | Green Bridge CBT

Question 1 Report

If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be

circular

oscillatory

rectilinear

rotational

Answer Details

If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be rectilinear. When an object moves with constant speed, it means that it covers the same distance in equal time intervals. On the other hand, acceleration is the rate of change of velocity with time. If an object undergoes acceleration, its velocity changes with time. Therefore, if a body moves with constant speed and undergoes an acceleration, it means that its direction of motion changes while it covers equal distances in equal time intervals. This type of motion is called rectilinear motion, where the object moves in a straight line, but its velocity changes due to the acceleration. In contrast, circular motion is when an object moves in a circular path with a constant speed, while oscillatory motion is when an object moves back and forth around a fixed point. Rotational motion is when an object rotates around an axis. None of these descriptions fit the scenario of a body moving with constant speed and undergoing acceleration, so the answer is rectilinear motion.

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Motion

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Question 2 Report

Which of the following characteristics of a wave is used in the measurement of the depth of the Sea?

diffraction

interference

refraction

reflection

Answer Details

Depth of sea can be measured by echo, a reflected sound waves.

Read lesson note on Properties Of Waves: Reflection, Refraction, Diffraction (WAEC)

Properties Of Waves: Reflection, Refraction, Diffraction

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Question 3 Report

"Sum of all forces acting on a body is zero." This condition represents equilibrium'

First condition

Second condition

Third condition

Fourth condition

Answer Details

First condition

View Answer

Question 4 Report

A metal rod has a length of 100cm at $200^\circ C$. At what temperature will its length be 99.4cm. If the linear expansivity of the material of the rod is $2 \times 10^{-5}C^{-1}$

200

^{o}

C

300

^{o}

C

100

^{o}

C

-100

^{o}

C

Answer Details

The linear expansivity of a material describes how its length changes with temperature. If the linear expansivity is given as 2 × 10^-5/°C, this means that for every 1°C change in temperature, the length of the material will change by 2 × 10^-5 times its original length. Given that the rod has a length of 100 cm at 200°C, we can use this information to find its length at a different temperature. If we let L be the length of the rod at temperature T, we can write the relationship as follows: L = 100 cm * (1 + 2 × 10^-5 * (T - 200°C)) To find the temperature at which the rod will have a length of 99.4 cm, we can set L equal to 99.4 cm and solve for T: 99.4 cm = 100 cm * (1 + 2 × 10^-5 * (T - 200°C)) 99.4 cm / 100 cm = 1 + 2 × 10^-5 * (T - 200°C) 0.994 = 1 + 2 × 10^-5 * (T - 200°C) -0.006 = 2 × 10^-5 * (T - 200°C) -0.006 / 2 × 10^-5 = T - 200°C -0.006 / (2 × 10^-5) = T - 200°C -0.006 / (2 × 10^-5) + 200°C = T So the temperature at which the rod will have a length of 99.4 cm is approximately equal to -0.006 / (2 × 10^-5) + 200°C, or -100°C. Therefore, the answer is -100°C.

Read lesson note on Thermal Expansion (JAMB)

Read lesson note on Temperature And Its Measurement (JAMB)

Thermal Expansion

Temperature And Its Measurement

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Question 5 Report

Calculate the velocity ratio of a screw jack of pitch 0.2cm if the length of the tommy bar is 23cm

230

π

23

π

70

π

140

π

Answer Details

P = 0.2cm, L = r = 23cm

VR

=

2?rP

=

2?LP

=

2?×230.2

=

230?

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Simple Machines

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Question 6 Report

Water and Kerosine are drawn respectively into the two limbs of a Hare's apparatus. The destiny of water is $1.0\mathrm{g\,cm^{-3}}$ and the density of kerosine is $0.80\mathrm{g\,cm^{-3}}$. If the height of the water column is 20.0cm, calculate the height of the kerosine column.

1.6cm

16.0cm

20.0cm

25.0cm

Answer Details

Devices with different liquids
d $_{1}$ h $_{1}$ = d $_{2}$ h $_{2}$
1 × 20 = 0.8 × h

h

=

200.8

=

25cm

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 7 Report

If the time of flight is 96seconds, calculate the horizontal range through the point of projection.

84400m

69000m

61440m

24000m

Answer Details

Time of flight, T = 96s
R = (Ucosθ) *time* T = 640 × 96 = 61,440m

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Motion

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Question 8 Report

The diagram shows four positions of the bob of a simple pendulum. At which of these positions does the bob have maximum kinetic energy and minimum potential energy

1

2

3

4

Answer Details

At position 1, the bob of the simple pendulum has the maximum potential energy and zero kinetic energy. At position 4, the bob has the maximum kinetic energy and minimum potential energy. To understand this, we need to know that the energy of a simple pendulum is converted back and forth between kinetic energy and potential energy as it swings back and forth. When the bob is at its highest point (position 1), it has the maximum potential energy because it is farthest from the ground and has the most potential to move downward. At this point, the bob has zero kinetic energy because it is momentarily at rest. As the bob swings downward towards the equilibrium point, it gains speed and its potential energy is converted to kinetic energy. At the equilibrium point (position 2), the bob has equal amounts of kinetic and potential energy. As the bob continues to move downward, its potential energy decreases and its kinetic energy increases. At position 3, the bob has minimum potential energy and some amount of kinetic energy. At the lowest point of its swing (position 4), the bob has maximum kinetic energy because it is moving at its fastest speed. At this point, the bob has minimum potential energy because it is closest to the ground and has the least amount of potential to move downward. So, to summarize, the bob has maximum potential energy at position 1, equal amounts of kinetic and potential energy at position 2, minimum potential energy at position 3, and maximum kinetic energy at position 4.

Read lesson note on Newton’s Laws Of Motion (WAEC)

Read lesson note on Equilibrium Of Forces (WAEC)

Newton’s Laws Of Motion

Equilibrium Of Forces

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Question 9 Report

A rectangular solid black has length 10cm, breadth 5cm and height 2cm. If it lies on a horizontal surface, and has density $100\text{kg/m}^3$, calculate the pressure it exerts on the surface.

200 N/m

^{2}

100 N/m

^{2}

400 N/m

^{2}

Answer Details

To calculate the pressure that the rectangular solid exerts on the surface, we need to use the formula for pressure: Pressure = Force / Area In this case, the force is the weight of the rectangular solid, which we can calculate using the formula: Weight = Mass x Gravity The mass of the rectangular solid can be calculated using its density and volume: Mass = Density x Volume The volume of the rectangular solid is simply its length x breadth x height: Volume = Length x Breadth x Height = 10 cm x 5 cm x 2 cm = 100 cm3 We need to convert this volume to cubic meters to use the density given in kg/m3: Volume = 100 cm3 = 0.0001 m3 Now we can calculate the mass: Mass = Density x Volume = 100 kg/m3 x 0.0001 m3 = 0.01 kg The gravity is the acceleration due to gravity, which we can assume to be 9.81 m/s2. Therefore, the weight is: Weight = Mass x Gravity = 0.01 kg x 9.81 m/s2 = 0.0981 N Now we can use this weight to calculate the pressure on the surface. The surface area in contact with the rectangular solid is simply its length x breadth: Area = Length x Breadth = 10 cm x 5 cm = 50 cm2 We need to convert this area to square meters: Area = 50 cm2 = 0.005 m2 Therefore, the pressure is: Pressure = Force / Area = 0.0981 N / 0.005 m2 = 19.62 N/m2 We can convert this to units of N/cm2 or N/mm2 if desired. This is equivalent to: Pressure = 0.1962 N/cm2 = 0.0001962 N/mm2 So the pressure that the rectangular solid exerts on the surface is 19.62 N/m2, which is approximately 20 N/m2. Therefore, the answer is 200 N/m2.

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Pressure

Measurements And Units

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Question 10 Report

A boy pushes a 500kg box along a floor with a force of 2000N. If the velocity of the box is uniform, the co-efficient of friction between the box and the floor is

1

0.8

0.65

0.4

Answer Details

The coefficient of friction is a measure of the amount of friction between two surfaces. It is represented by the symbol "μ" and is a dimensionless quantity. The coefficient of friction between two surfaces depends on the nature of the surfaces in contact and the force pressing them together. In this problem, the boy is pushing the box with a force of 2000N. If the box is moving with a uniform velocity, then the force of friction acting on the box is equal and opposite to the pushing force applied by the boy. We can calculate the force of friction using the formula: frictional force = coefficient of friction x normal force where the normal force is the force exerted by the floor on the box in a direction perpendicular to the floor. Since the box is not moving up or down, the normal force is equal to the weight of the box. The weight of the box can be calculated using the formula: weight = mass x gravity where mass is the mass of the box and gravity is the acceleration due to gravity (9.8 m/s^2). So, the weight of the box is: weight = 500 kg x 9.8 m/s^2 = 4900 N The force of friction is equal to the pushing force of 2000N, so we can set these two equal to each other and solve for the coefficient of friction: frictional force = 2000N coefficient of friction x normal force = 2000N coefficient of friction x 4900N = 2000N coefficient of friction = 2000N / 4900N = 0.408 So, the coefficient of friction between the box and the floor is approximately 0.4. Therefore, the correct answer is 0.4.

Read lesson note on Equilibrium Of Forces (WAEC)

Read lesson note on Measurements And Units (JAMB)

Equilibrium Of Forces

Measurements And Units

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Question 11 Report

The point at which the molecules of a loaded wire begin to slide across each other resulting in a rapid increase in extension is

yield point

proportionality point

deformation point

elastic point

Answer Details

The point at which the molecules of a loaded wire begin to slide across each other resulting in a rapid increase in extension is called the yield point. At this point, the material no longer behaves elastically and becomes permanently deformed. The yield point is an important parameter in material science and engineering as it indicates the maximum stress a material can withstand before it begins to deform plastically. Therefore, the yield point is a critical factor to consider when designing materials for specific applications.

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Elasticity

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Question 12 Report

The diagram above represents the stress-strain graph of a loaded wire. Which of these statements is correct?

At J, the wire becomes plastic

J is the yield point

L is the elastic limit

At K, the wire breaks

Answer Details

- I is the elastic limit
- the end of the constant part J is the yield point
- L is the break point.

Read lesson note on Elasticity (JAMB)

Read lesson note on Measurements And Units (JAMB)

Elasticity

Measurements And Units

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Question 13 Report

A copper rod, 5m long when heated through 20c, expands by 1mm. If a second copper rod, 2.5m long is heated through 5c, by how much will it expand?

4mm

2mm

0.25mm

0.12mm

Answer Details

l $_{1}$ = 5m, ΔT = 10c, l $_{2}$ - l $_{1}$ = 1mm
l $_{1}$ = 2.5m, ΔT = 5c, l $_{2}$ - l $_{1}$ = ?

using

α

=

l

_{2}

- l

_{1}

l

_{1}

ΔT

15(10)

=

l

_{2}

- l

_{1}

2.5(5)

l

_{2}

-

l

_{2}

=

2.5(5)5(10)

=

14

=

0.25mm

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 14 Report

Neutrons were discovered by

Faraday

Dalton

James Chadwick

Rutherford

Answer Details

Neutrons were discovered by James Chadwick. In 1932, he conducted an experiment in which he bombarded a thin sheet of beryllium with alpha particles. He observed that a new type of radiation was emitted that was not affected by electric or magnetic fields. He concluded that this radiation was composed of particles that were neutral and had a mass similar to that of a proton. He called these particles "neutrons," and his discovery revolutionized our understanding of atomic structure and led to the development of nuclear energy.

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Structure Of The Atom (Nigeria Only)

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Question 15 Report

A thermocouple thermometer is connected to a millivoltmeter which can read up to 10mV. When one junction is in ice at 0°C and the other is steam at 100°C, the millivoltmeter reads 4mV. What is the maximum temperature which this arrangement can measure

100

^{o}

C

248

^{o}

C

250

^{o}

C

350

^{o}

C

Answer Details

The maximum temperature which this arrangement can measure is 250°C. A thermocouple thermometer works by using the thermoelectric effect, which is the phenomenon that occurs when two dissimilar metals are joined together to form a loop and a temperature difference is established between the two junctions. This temperature difference generates a small electrical voltage, which can be measured using a millivoltmeter. The voltage generated is proportional to the temperature difference between the two junctions. In the case of the thermocouple thermometer described, one junction is in ice at 0°C and the other is steam at 100°C, and the millivoltmeter reads 4mV. This means that the voltage generated by the thermocouple is 4 millivolts, which corresponds to a temperature difference of 100°C. However, the millivoltmeter can only read up to 10mV, so the maximum temperature difference it can measure is 10mV / 4mV/°C = 250°C. This means that the maximum temperature which this arrangement can measure is 250°C.

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Temperature And Its Measurement

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Question 16 Report

The angular dispersion of a prism depends on

The index of refraction only

The angle of incidence as well as the index of refraction

The angle of incidence only

The thickness of the prism only

Answer Details

Dispersion is due to different refractive indices speeds and wavelengths.

Read lesson note on Reflection Of Light At Plane And Curved Surfaces (JAMB)

Read lesson note on Refraction Of Light Through Plane And Curved Surfaces (JAMB)

Reflection Of Light At Plane And Curved Surfaces

Refraction Of Light Through Plane And Curved Surfaces

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Question 17 Report

The mass of water vapour in a given volume of air is 0.05g at 20°C, while the mass of water vapour required to saturate it at the same temperature is 0.15g. Calculate the relative humidity of the air.

3.33%

5.55%

33.33%

55.55%

Answer Details

Relative humidity is a measure of how much water vapor the air is holding compared to the maximum amount it could hold at a given temperature. It is expressed as a percentage. To calculate the relative humidity of the air in this problem, we need to use the formula: Relative humidity = (mass of water vapor in air / mass of water vapor required for saturation) x 100% We are given that the mass of water vapor in the air is 0.05g and the mass of water vapor required for saturation at the same temperature is 0.15g. Plugging these values into the formula, we get: Relative humidity = (0.05 / 0.15) x 100% = 33.33% Therefore, the relative humidity of the air is 33.33%. So the answer is 33.33%.

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Quantity Of Heat

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Question 18 Report

The height at which the atmosphere cases to exist is about 80km. If the atmospheric pressure on the ground level is 760mmHg, the pressure at a height of 20km above the ground level is

$(\rho_m = 13.6g/cm^3\ \rho = 0.00013g/cm^3)$

380mmHg

570mmHg

190mmHg

480mmHg

Answer Details

ρ $_{m}$ h $_{m}$ = ρ $_{a}$ h $_{a}$
13.68(760 - p) × 10 $^{- 3}$ = 13 × 10 $^{- 5}$ (20 × 10 $^{3}$ )

760

-

p

=

13 × 10

^{- 5}

× 20 × 10

^{3}

13.68 × 10

^{- 3}

=

19.00

×

10

^{1}

760 - p = 190
p = 760 - 190 = 570mmHg

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Pressure

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Question 19 Report

Ripple in a power supply unit is caused by

using an alternating current source

forward voltage drop

heavy load

using a zener diode

Answer Details

The correct option is "Using a zener diode" as fluctuation of d.c signal results from the rectification of a.c to d.c.

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Electrostatics

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Question 20 Report

Which of the following equations is the correct definition of the reactance of an indicator L?

Reactance = (Amplitude of voltage)

\div

(Amplitude of current)

Reactance = (Amplitude of voltage) x (Amplitude of current)

Reactance = (Amplitude of current)

^{2}

\div

(Amplitude of voltage)

Reactance = (Amplitude of current)

^{2}

\div

(Amplitude of voltage)

\frac{1}{2}

Answer Details

The correct definition of the reactance of an inductor L is: Reactance = (Amplitude of voltage) ÷ (Amplitude of current) The reactance of an inductor is a measure of the opposition offered by the inductor to the flow of alternating current (AC). It is denoted by the symbol Xl and is measured in ohms. When AC flows through an inductor, a magnetic field is generated around the inductor, which opposes any changes in the current flowing through it. This opposition to the flow of current is called reactance. The reactance of an inductor depends on its inductance, frequency of the AC signal, and the amplitude of the AC signal. However, the reactance of an inductor is directly proportional to the frequency of the AC signal and the inductance of the inductor. The reactance of an inductor is also affected by the amplitude of the AC signal, but this effect is not as significant as the other two factors. is the correct definition of the reactance of an inductor, as it expresses the ratio of the amplitude of voltage to the amplitude of current, which is a common way to define reactance. is incorrect, as it represents the power delivered by the AC signal, not the reactance. and are also incorrect, as they involve squaring either the amplitude of current or the amplitude of voltage, which is not a valid method of calculating reactance. Therefore, the correct option is.

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Electric Field

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Question 21 Report

A ray of light passes through the centre of curvature of a concave mirror and strikes the mirror. At what angle is the ray reflected?

180

^{o}

90

^{o}

0

^{o}

60

^{o}

Answer Details

When a light ray passes through the center of curvature of a concave mirror and strikes the mirror, the reflected ray will be reflected back on itself, creating an angle of 0 degrees. Therefore, the correct answer is 0o.

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Question 22 Report

When a girl moves towards a plane mirror at a speed of 4.0m/s, the distance between the girl and her image reduces a speed of

2 m/s

4 m/s

8 m/s

12 m/s

Answer Details

v

=

dt

or

v

α

d

d = x, v = 4m/s
d = 2x, v = ? (girl and image)

v

=

2 × 4x

=

8

ms

Read lesson note on Reflection Of Light At Plane And Curved Surfaces (JAMB)

Reflection Of Light At Plane And Curved Surfaces

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Question 23 Report

Three resistors with resistance 200Ω, 500Ω and 1kΩ are connected in series. A 6v battery is connected to either end of the combination. Calculate the potential difference between the ends of 200Ω resistance.

0.71V

0.7V

0.82V

0.8V

Answer Details

To calculate the potential difference between the ends of the 200Ω resistance, we need to use Ohm's Law, which states that the potential difference (V) across a resistor is equal to the current (I) flowing through the resistor multiplied by the resistance (R) of the resistor. First, we need to find the total resistance of the series combination of resistors. We add up the individual resistances: Total resistance = 200Ω + 500Ω + 1kΩ = 1.7kΩ Next, we can use Ohm's Law to find the current flowing through the circuit. We know that the battery voltage is 6V, and the total resistance is 1.7kΩ: I = V / R = 6V / 1.7kΩ = 0.0035A Now we can use Ohm's Law again to find the potential difference across the 200Ω resistor: V = IR = 0.0035A * 200Ω = 0.7V Therefore, the potential difference between the ends of the 200Ω resistance is 0.7V. The correct answer is option B.

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Current Electricity

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Question 24 Report

Which of these is observed when air is pumped out of a discharge tube without lowering its pressure

the conductivity of the air increases

the conductivity of the air decreases

conduction does not occur

spark are produced

Answer Details

Conduction takes places in gases when air is pumped out of a discharged tube under reduced pressure.

View Answer

Question 25 Report

The earth's gravitational field intensity at its surface is about

$G = 6.7 \times 10^{-11}\,\mathrm{Nm^2/kg^2}$, mass of the earth is $6 \times 10^{24}\,\mathrm{kg}$, radius of the earth is $6.4 \times 10^6\,\mathrm{m}$, g on the earth = $9.8\mathrm{m/s^2}$

6.7N/kg

7.9N/kg

8.0N/kg

9.8N/kg

Answer Details

The earth's gravitational field intensity at its surface can be calculated using the formula: g = G * M / r^2 where G is the gravitational constant, M is the mass of the earth, r is the radius of the earth, and g is the gravitational field intensity at the surface of the earth. Substituting the given values, we get: g = (6.7 × 10^-11 Nm^2/kg^2) * (6 × 10^24 kg) / (6.4 × 10^6 m)^2 g = 9.8 N/kg (approx.) Therefore, the answer is 9.8N/kg.

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Gravitational Field

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Question 26 Report

Lamps in domestic lightings are usually in

series

divergent

convergent

parallel

Answer Details

Lamps in domestic lighting are usually connected in parallel. This means that each lamp is connected directly to the power supply, rather than being connected in a series or divergent or convergent configuration. In a parallel configuration, each lamp operates independently of the others, and if one lamp fails, the other lamps will continue to function. This is an important feature for domestic lighting, as it ensures that a single lamp failure will not leave the entire room in darkness. Additionally, in a parallel configuration, each lamp can be controlled independently, for example by a switch or dimmer, without affecting the operation of the other lamps. This allows for greater flexibility in lighting design and control. In summary, lamps in domestic lighting are usually connected in parallel because it allows for independent operation of each lamp and ensures that a single lamp failure does not affect the operation of the others.

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Capacitors

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Question 27 Report

If the attraction of the sun is suddenly ceased, the earth would continue to move in a straight line making a tangent with the original orbit. This statement is derived from Neutron's

First law of motion

Second law of motion

Third law of motion

Law of universal gravitation

Answer Details

The correct answer is the First law of motion. The First law of motion, also known as the law of inertia, states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. In this case, the earth is moving in its orbit around the sun because of the force of gravity between the two objects. If the force of gravity suddenly ceased, the earth would no longer be acted upon by an external force and would continue to move in a straight line, making a tangent with its original orbit. This idea is attributed to Sir Isaac Newton, who developed the laws of motion and the law of universal gravitation. However, the specific statement mentioned in the question is derived from the First law of motion.

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Newton’s Laws Of Motion

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Question 28 Report

A vibrator causes water ripples to travel across the surface of a tank. The wave travels 50cm in 2s and the distance between successive crests is 5cm. Calculate the frequency of the vibrator

5Hz

6Hz

5.2Hz

25Hz

Answer Details

The frequency of the vibrator can be calculated using the formula: frequency = speed / wavelength where speed is the speed of the wave, and wavelength is the distance between successive crests. In this case, we are given that the wave travels 50cm in 2s, which means the speed of the wave is: speed = distance / time = 50cm / 2s = 25cm/s We are also given that the distance between successive crests is 5cm, which is the wavelength. Therefore, the frequency of the vibrator is: frequency = speed / wavelength = 25cm/s / 5cm = 5Hz So the correct answer is 5Hz.

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Motion

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Question 29 Report

Electrons were discovered by

Dalton

James Charwick

J.J. Thompson

Niels Bohr

Answer Details

Electrons were discovered by J.J. Thompson. In the late 19th century, he performed a series of experiments using cathode ray tubes, which are glass tubes containing low-pressure gas and electrodes. By applying high voltage, he observed a beam of negatively charged particles traveling from the negative electrode to the positive electrode. He concluded that these particles, which he called "corpuscles," were fundamental units of negative charge and later were renamed electrons. This discovery led to the development of the modern understanding of atomic structure and the electron's role in it.

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Structure Of The Atom (Nigeria Only)

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Question 30 Report

The lead-acid accumulator consists of

lead as the positive electrode

lead acid as the negative electrode

hydrochloric acid as the electrolyte

tetraoxosulphate (vi) acid as the electrolyte

Answer Details

- the positive pole is lead peroxide (PbO

_{2}

)
- the negative pole is head
- the electrolyte is H

_{2}

SO

_{4}

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Electric Cells

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Question 31 Report

The lower fixed part of a faulty thermometer reads 2°C while the upper fixed point is 100°C.

What is the true temperature when the thermometer reads 51°C?

52°C

50°C

49°C

46°C

Answer Details

Since the thermometer is faulty, it is not measuring the temperature accurately. To find the true temperature, we need to determine the extent of the error in the thermometer. We can do this by comparing the difference between the lower fixed point and the reading with the difference between the upper fixed point and the true temperature. Since the lower fixed point reads 2°C and the upper fixed point reads 100°C, and the thermometer reading is 51°C, we can calculate the error as follows: True temperature = (51°C - 2°C) / (51°C - 2°C) * (100°C - 51°C) + 51°C = 50°C So, the true temperature when the thermometer reads 51°C is 50°C, which is option B.

Read lesson note on Quantity Of Heat (JAMB)

Read lesson note on Temperature And Its Measurement (JAMB)

Quantity Of Heat

Temperature And Its Measurement

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Question 32 Report

The part of the human eye that does similar work as the diaphragm of a camera lens is the

Ciliary muscles

Pupil

Iris

Retina

Answer Details

The part of the human eye that does similar work as the diaphragm of a camera lens is the iris. The iris is the colored part of the eye and is responsible for controlling the amount of light that enters the eye. Just like the diaphragm in a camera lens, the iris can adjust its size to allow more or less light into the eye. This helps to regulate the amount of light reaching the retina, which is responsible for sensing light and transmitting the image to the brain.

Read lesson note on Structure Of The Atom (Nigeria Only) (WAEC)

Structure Of The Atom (Nigeria Only)

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Question 33 Report

Which of the following statements are correct of the production and propagation of waves?

I. vibration produces waves

II. waves transmit energy along the medium

III. the medium through which the wave travels does not travel with the wave

IV. waves do not require any medium for transmission

I and IV only

II and IV only

III and IV only

I, II and III only

Answer Details

The correct statement is: I and II and III only. Explanation: - Statement I is correct because the production of waves involves some kind of disturbance that creates a vibration in the medium, which then propagates as a wave. - Statement II is correct because waves carry energy along the medium as they propagate. This is why waves can be used to transmit information or power over long distances. - Statement III is correct because the medium through which a wave travels does not move with the wave. Instead, the wave passes through the medium, causing it to oscillate or vibrate, but not to move along with the wave. - Statement IV is incorrect because most waves require a medium through which to propagate. For example, sound waves require air, water waves require water, and seismic waves require the Earth's crust. There are some types of waves, such as electromagnetic waves, that can propagate through a vacuum, but this is not true for all waves.

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Production And Propagation Of Waves

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Question 34 Report

If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be

oscillation

circular

rotational

rectilinear

Answer Details

If a body moves with a constant speed but at the same time undergoes an acceleration, its motion is called rectilinear motion. This means that the body moves in a straight line and its speed changes at a constant rate, causing an acceleration. It is different from oscillation, circular and rotational motions which involve changes in direction, as well as changes in speed.

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Rectilinear Acceleration

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Question 35 Report

In semi-conductor, the carriers of current at room temperature are

electrons only

electrons and holes

holes only

electron and ions

Answer Details

In a semiconductor, the carriers of current at room temperature are both electrons and holes. Semiconductors are materials with properties that are in between those of conductors (e.g. metals) and insulators (e.g. rubber). At room temperature, a semiconductor crystal contains both free electrons and positively charged vacancies called holes. When a voltage is applied across the semiconductor, the electrons move towards the positive end of the circuit and the holes move towards the negative end. This movement of charge carriers constitutes an electric current. In summary, both electrons and holes can carry current in a semiconductor at room temperature, making the correct answer.

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Capacitors

Electrostatics

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Question 36 Report

The resultant capacitance in the figure above is

0.4μf

0.8μf

1.8μf

4.5μf

Answer Details

For the parallel arrangement = 2 + 4 = 6μf

For

the

series

arrangement

=

1C

_{T}

=

12

+

13

+

16

+

14

1C

_{T}

=

1512

C

_{T}

=

1215

=

0.8μf

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Capacitors

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Question 37 Report

Which of the following bodies, each with centre of gravity G, lying on a horizontal table, is/are in unstable equilibrium?

II only

III only

I and IV only

II and III only

Answer Details

- I and II are in neutral equilibrium. They will roll continuously on the table
- III is a body with high centre of gravity (unstable)
- IV is a body with high centre of gravity (stable)

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Equilibrium Of Forces

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Question 38 Report

Which of the following is/are the limitations to the Rutherford's atomic models?

I. It is applicable when energy is radiated as electrons are revolving

II. It is applicable when energy is radiated in a continuous mode

III. It is applicable to an atom with only one electron in the other shell

I only

II only

I and II only

I, II and III only

Answer Details

Rutherford assumed that (I) energy is radiated when electrons are revolving (II) energy is radiated in a continuous mode. These are limitations of Rutherford's model

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Structure Of The Atom (Nigeria Only)

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Question 39 Report

A well 1km deep is filled with a liquid of density $950\text{kg/m}^3$ and $g = 10\text{m/s}^2$, the pressure at the bottom of the well is

9.6 × 10

^{6}

N/m

^{2}

9.5 x 10

^{5}

N/m

^{2}

9.4 x 10

^{6}

N/m

^{2}

9.5 x 10

^{6}

N/m

^{2}

Answer Details

P = Pa + ρgh = (1.00 × 10

^{5}

) + (950 × 10 × 1000)
P = 10

^{5}

+ (95 × 10

^{5}

) = 10

^{5}

(1 + 95) = 96 × 10

^{5}

P = 9.6 × 10

^{6}

N/m

^{2}

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Read lesson note on Motion (WAEC)

Pressure

Motion

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Question 40 Report

The diagram shows a uniform meter rule AB which balances horizontally at the 90cm mark when a mass of 0.2kg is suspended from B. Calculate the mass of the meter rule.

0.05kg

0.20kg

0.80kg

1.00kg

Answer Details

M $_{r}$ (90 - 50) = 0.2(100 - 90)
40M $_{r}$ = 0.2 × 10

M $_{r}$ = $\frac{2}{40}$ = 0.05kg

Read lesson note on Measurements And Units (JAMB)

Measurements And Units

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