The angular dispersion of a prism depends on

The angle of incidence as well as the index of refraction

The thickness of the prism only

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

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

Gases conduct electricity under

normal pressure and low voltage

- 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

A mass of 0.5kg is whirled in a vertical circle of radius 2m at a steady rate of 2 rev/s. Calculate the centripetal force

164N

160N

158N

172N

Answer Details

The centripetal force is the force that acts towards the center and keeps an object moving in a circular path. To calculate the centripetal force, we can use the following formula: f = m * v^2 / r where: - f = centripetal force - m = mass of the object (0.5 kg) - v = velocity of the object (2 rev/s * 2 * pi m/rev = 12.57 m/s) - r = radius of the circle (2 m) Plugging in the values, we get: f = 0.5 kg * 12.57 m/s^2 / 2 m f = 31.43 N Rounding to the nearest whole number, the centripetal force is 31 N. So, the closest answer from the options is 160N.

Read lesson note on Temperature And Its Measurement (JAMB)

Read lesson note on Speed And Velocity (WAEC)

Read lesson note on Equilibrium Of Forces (WAEC)

Temperature And Its Measurement

Speed And Velocity

Equilibrium Of Forces

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Question 2 Report

Which of the following is consistent with Charles' law?

I

II

III

IV.

I

II

III

IV

Answer Details

This is the correct graph. The graph is volume against 1/ temperature where temperature is in Celsius.

Read lesson note on Gas Laws (JAMB)

Read lesson note on Temperature And Its Measurement (JAMB)

Gas Laws

Temperature And Its Measurement

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Question 3 Report

The volume of a stone having an irregular shape can be determined using?

meter rule

measuring cylinder

vernier calliper

micrometer screw gauge

Answer Details

The volume of a stone with an irregular shape can be determined using a measuring cylinder. A measuring cylinder is a glass or plastic container with a narrow cylindrical shape and markings on the side to indicate the volume it contains. To determine the volume of an irregularly shaped stone, you would fill the measuring cylinder with water, carefully lower the stone into the water, and note the increase in the volume of the water. The difference in the volume of the water before and after the stone was added is equal to the volume of the stone. The meter rule, vernier calliper, and micrometer screw gauge are all measuring instruments, but they are not designed to measure the volume of irregularly shaped objects. The meter rule is a measuring tool used for measuring length. The vernier calliper is used for measuring the diameter of objects, and the micrometer screw gauge is used for precise measurements of small distances.

Read lesson note on Measurements And Units (JAMB)

Measurements And Units

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Question 4 Report

Which of the following statements is/are correct for a freely falling body?

I. the total is entirely kinetic

II. the ratio of potential energy to kinetic energy is constant

III. the sum of potential and kinetic energy is constant

I only

II only

III only

I and III only

Answer Details

The correct answer is "III only". A freely falling body is one that is falling under the influence of gravity and experiences no other force or constraint. In this situation, the total energy of the body is conserved, meaning that the sum of its potential and kinetic energy remains constant. The potential energy of a body is directly proportional to its height above the ground, and its kinetic energy is directly proportional to its velocity. As the body falls, its potential energy decreases and its kinetic energy increases, but the total energy remains constant. Statement III is correct because the sum of potential and kinetic energy is indeed constant for a freely falling body. Statement I is incorrect because the body has both potential and kinetic energy, so the total energy is not entirely kinetic. Statement II is incorrect because the ratio of potential energy to kinetic energy is not constant for a freely falling body, as both are changing as the body falls.

Read lesson note on Work, Energy And Power (WAEC)

Work, Energy And Power

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Question 5 Report

In the molecular explanation of conduction, heat is transferred by the

Free electrons

Free atoms

Free molecules

Free solids

Answer Details

In the molecular explanation of conduction, heat is transferred by the Free electrons. In metals, free electrons move randomly and collide with other particles as they gain kinetic energy. These free electrons transfer the energy to the adjacent particles, which in turn gain kinetic energy and transmit it to other adjacent particles, thus transferring heat energy from one part of the material to another. This process of heat transfer by free electrons is called conduction. Therefore, the correct option is "Free electrons."

Read lesson note on Thermal Expansion (JAMB)

Thermal Expansion

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Question 6 Report

The following are parts of the eye

I. Retina

II. Pupil

III. Iris

The correct equivalent in the camera in the same order are

Diaphragm, Aperture, film

Aperture, Diaphragm, Film

Film, Diaphragm, Aperture

Film, Aperture, Diaphragm

Answer Details

- retina is similar to film
- pupil is similar to aperture
- iris is similar to diaphragm

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

Structure Of The Atom (Nigeria Only)

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Question 7 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.

Read lesson note on Electric Field (WAEC)

Electric Field

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Question 8 Report

The volume of 0.354g of helium at 273°C and 114cm of mercury pressure is 2667cm$^{3}$. Calculate the volume

2000.25 cm

^{3}

200.025 cm

^{3}

4003.27 cm

^{3}

2010.25 cm

^{3}

Answer Details

m = 0.354g, T $_{1}$ = 273°C = 273 + 273 = 576K
P $_{1}$ = 114cmHg, V $_{1}$ = 2667cm $^{3}$ at STP
T $^{2}$ = 273K, P $_{2}$ = 76cmHg, V $_{2}$ = ?

P

^{1}

V

^{1}

T

^{1}

=

P

^{2}

V

^{2}

T

^{1}

V

_{2}

=

114 × 2667 × 27376 × 576

=

2000.25cm

^{3}

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 9 Report

In Sunlight, a blue flower looks blue because we see the flower by the light it

receives from our eyes

disperses

absorbed

reflect

Answer Details

In sunlight, a blue flower looks blue because it reflects blue light. When sunlight falls on an object, the object can either absorb, transmit, or reflect the light. The color of an object that we see is determined by the light that is reflected by that object. For example, if an object appears blue, it is because it reflects blue light and absorbs other colors. In the case of a blue flower in sunlight, the petals of the flower reflect blue light and absorb other colors. This reflected blue light enters our eyes, and our brain interprets it as the color blue. Therefore, we see the blue flower as blue because it reflects blue light, and that is the color that enters our eyes. In summary, the reason why a blue flower looks blue in sunlight is that it reflects blue light and absorbs other colors.

Read lesson note on Electromagnetic Waves: Types Of Radiation In Electromagnetic Spectrum (WAEC)

Read lesson note on Wave-particle Paradox (WAEC)

Read lesson note on Structure Of The Nucleus (WAEC)

Electromagnetic Waves: Types Of Radiation In Electromagnetic Spectrum

Wave-particle Paradox

Structure Of The Nucleus

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Question 10 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 11 Report

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because

all the heat is used to break the bonds holding the molecules of the solid together

the heat capacity has become very large as the substance melts

the heat energy is quickly conducted away

the heat gained is equal to the heat lost by the substance

Answer Details

When a solid is heated to its melting point, the heat supplied is used to overcome the intermolecular forces holding the molecules in a fixed position, resulting in the breaking of these bonds. As a result, the solid transforms into a liquid without any change in temperature. This is because the heat energy supplied is used in breaking the bonds between molecules rather than increasing the kinetic energy of the molecules, which is what causes an increase in temperature. Therefore, the correct option is: "all the heat is used to break the bonds holding the molecules of the solid together."

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Change Of State

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Question 12 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 13 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.

Read lesson note on Motion (JAMB)

Motion

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Question 14 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.

Read lesson note on Current Electricity (JAMB)

Current Electricity

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Question 15 Report

A body moves in SHM between two point 20m on the straight line Joining the points. If the angular speed of the body is 5 rad/s. Calculate its speed when it is 6m from the center of the motion.

20 m/s

30 m/s

40 m/s

50 m/s

Answer Details

From two parts 20m apart
a = 10m, x = 6m, A = 5
V = ω

\sqrt{A^{2} - X^{2}}

= 5

\sqrt{10^{2} - 6^{2}}

= 40m/s

Read lesson note on Simple Harmonic Motion (WAEC)

Simple Harmonic Motion

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Question 16 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}

Read lesson note on Electric Cells (JAMB)

Electric Cells

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Question 17 Report

In which of the points labelled A, B, C, D and E on the conductor shown would electric charge tend to concentrate most

A

B

C

E

Answer Details

- Charge are mostly concentrated at the outermost part of a hollow conductor
- Charge are also mostly concentrated at the pointed ends or places with high density point.

Read lesson note on Electric Field (WAEC)

Read lesson note on Electrostatics (JAMB)

Electric Field

Electrostatics

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Question 18 Report

The value of T in the figure above is

30N

10.0N

20N

40N

Answer Details

Tsin30 + Tsin30 =40

2Tsin30 = 40

Tsin30 = 40/2 = 20

T( $\frac{1}{2}$ ) = 20

T = 20 x 2 = 40N

Read lesson note on Scalars And Vectors (JAMB)

Read lesson note on Motion (JAMB)

Scalars And Vectors

Motion

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Question 19 Report

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

is a light material

is a good conductor

is a good insulator

can be converted into thin sheets

Answer Details

- Aluminium can be made in thin sheet like Gold.
- the leaf is a thin material that can be diverged easily.

Read lesson note on Electrostatics (JAMB)

Electrostatics

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Question 20 Report

According to kinetic molecular model, in gases

The molecules are very fast apart and occupy all the space made available.

The particles occur in clusters with molecules slightly farther apart.

The particles are closely packed together, they occupy minimum space and are usually arranged in a regular pattern.

The particles vibrate about fixed positions and are held together by the strong inter-molecular bond between them.

Answer Details

In kinetic molecular model, gases are energised and thus moves freely, fast as they occupy specific space

Read lesson note on Gas Laws (JAMB)

Read lesson note on Quantity Of Heat (JAMB)

Read lesson note on Thermal Expansion (JAMB)

Read lesson note on Structure Of Matter And Kinetic Theory (JAMB)

Gas Laws

Quantity Of Heat

Thermal Expansion

Structure Of Matter And Kinetic Theory

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Question 21 Report

A car moving at 20m/s with its horn blowing (f = 1200Hz) is chasing another car going at 15m/s. What is the apparent frequency of the horn as heard by the driver being chased?

1.22KHz

2.40KHz

8.12KHz

1.22Hz

Answer Details

f

_{1}

=

f(v - v

_{o}

)v - v

_{s}

=

1200(340 - 15)340 - 20

=

1.22KHz

Read lesson note on Position, Distance And Displacement (WAEC)

Position, Distance And Displacement

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Question 22 Report

A microscope is focused on a mark on a table, when the mark is covered by a plate of glass 2m thick, the microscope has to be raised 0.67cm for the mark to be once more in focus. Calculate the refractive index.

1.52

1.68

2.58

1.82

Answer Details

R = th = 2cm, d = 0.67cm

n

=

RA

=

RR.d

=

22-0.67

=

1.52

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

Refraction Of Light Through Plane And Curved Surfaces

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Question 23 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.

Read lesson note on Capacitors (JAMB)

Read lesson note on Electrostatics (JAMB)

Capacitors

Electrostatics

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Question 24 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 25 Report

A mixture of blue and red pigment when illuminated by white light will appear

green

orange

purple

magenta

Answer Details

A mixture of blue and red pigment when illuminated by white light will appear purple. This is because when white light shines on a surface, it contains all the colors of the visible spectrum. When blue and red pigments are mixed together, they absorb all the other colors in the spectrum except for blue and red. Therefore, when white light shines on this mixture, the blue pigment absorbs all the colors except blue, while the red pigment absorbs all the colors except red. The result of this is that the blue and red pigments reflect only blue and red light, which then combines to form purple. Therefore, the mixture of blue and red pigments appears purple when illuminated by white light.

Read lesson note on Structure Of The Nucleus (WAEC)

Structure Of The Nucleus

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Question 26 Report

The distance between an object and its real image in a convex lens is 40cm. If the magnification of the image is 3, calculate the focal length of the lens

6.5 cm

7.5 cm

8.5 cm

4.5 cm

Answer Details

u + v = 40

$\frac{v}{u}$ = 3

v = 3u

u + 3u = 40

4u = 40

u = 10cm

v = 3u = 30cm

f = $\frac{u v}{u + v} = \frac{10 (30)}{10 + 30} = \frac{300}{40}$

= 7.5 cm

Read lesson note on Gravitational Field (WAEC)

Gravitational Field

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Question 27 Report

When the temperature of a liquid is increased, its surface tension

increases

decreases

remain constant

increases then decreases

Answer Details

Surface tension or elasticity of a fluid decreases with increased in temperature

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 28 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.

Read lesson note on Electrostatics (JAMB)

Electrostatics

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Question 29 Report

Which of the following statement about the electromagnet shown above is correct?

when the current flows from A to B, the end A will be in north pole

when the current flows from A to B, the end A will be south pole

when the current flows from A to B, the end B will be north pole

none of the above

Answer Details

A - B = S - N.
Also, starting end of the current is south while terminating end is North.

Read lesson note on Electric Field (WAEC)

Electric Field

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Question 30 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)

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Newton’s Laws Of Motion

Equilibrium Of Forces

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Question 31 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?

Read lesson note on Simple Machines (JAMB)

Simple Machines

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Question 32 Report

A straight wire 15cm long, carrying a current of 6.0A is in a uniform field of 0.40T. What is the force on the wire when it is at right angle to the field

0.46N

0.35N

0.36N

0,24N

Answer Details

The force on a current-carrying wire in a uniform magnetic field can be calculated using the equation: F = BILsinθ where F is the force in Newtons, B is the magnetic field strength in Tesla, I is the current in Amperes, L is the length of the wire in meters, and θ is the angle between the wire and the magnetic field. In this problem, the wire is 15cm long (0.15m), carrying a current of 6.0A, and the magnetic field is 0.40T. The angle between the wire and the magnetic field is 90 degrees (since the wire is at right angles to the field). Substituting the given values into the equation, we get: F = (0.40T)(6.0A)(0.15m)sin90 sin90 = 1, so we can simplify the equation to: F = (0.40T)(6.0A)(0.15m) F = 0.36N Therefore, the force on the wire is 0.36N. Answer option C is the correct answer.

Read lesson note on Force On A Current-Carrying Conductor In A Magnetic Field (JAMB)

Force On A Current-Carrying Conductor In A Magnetic Field

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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.

Read lesson note on Production And Propagation Of Waves (WAEC)

Production And Propagation Of Waves

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Question 34 Report

A man on a bench will exert the greatest pressure on the bench when he

lies flat on his back

lies flat on his belly

stands on both feet

stands on the toes of one foot

Answer Details

The man on the bench will exert the greatest pressure when he stands on the toes of one foot. This is because when he stands on one foot, all his weight is concentrated on a smaller surface area of the bench, resulting in more pressure. The pressure he exerts is calculated by dividing his weight by the surface area in contact with the bench. When he stands on one foot, the surface area is smaller, which means the pressure exerted is greater. In comparison, when he lies flat on his back or belly, or when he stands on both feet, his weight is distributed over a larger surface area, resulting in less pressure.

Read lesson note on Pressure (JAMB)

Read lesson note on Measurements And Units (JAMB)

Pressure

Measurements And Units

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Question 35 Report

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 kinetic energy of the body

an increase in the potential energy of the body

an increase in the height of the body

Answer Details

The condition for stable equilibrium of a body that has been slightly displaced from its equilibrium position is "an increase in the potential energy of the body." When an object is at its equilibrium position, it has a minimum potential energy. When the object is displaced from its equilibrium position, it has a higher potential energy. For the object to be in stable equilibrium, it must be able to return to its equilibrium position after it has been displaced. If the potential energy of the object increases as it is displaced, it means that the equilibrium position is a point of stable equilibrium. This is because the object will experience a restoring force that will push it back towards its equilibrium position, as the potential energy decreases. Therefore, an increase in potential energy is a condition for a body to be in stable equilibrium after it has been slightly displaced from its equilibrium position. An increase in kinetic energy or height does not necessarily indicate stability, as it depends on the specific situation and other factors at play.

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

Read lesson note on Scalars And Vectors (JAMB)

Read lesson note on Equilibrium Of Forces (WAEC)

Newton’s Laws Of Motion

Scalars And Vectors

Equilibrium Of Forces

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Question 36 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 37 Report

The mass of a nucleus is the

total number of its proton and neutrons

number of its protons

mass of its electrons

total number of its protons and electrons

Answer Details

The mass of a nucleus is the total number of its protons and neutrons. The protons and neutrons are the subatomic particles that make up the nucleus of an atom. The mass of an atom is mostly concentrated in its nucleus, and the electrons orbiting the nucleus have a much smaller mass. Therefore, the mass of an atom is mostly determined by the number of protons and neutrons in its nucleus. The number of protons determines the element, and the number of neutrons can vary, resulting in isotopes of that element.

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Structure Of The Nucleus

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Question 38 Report

According to kinetic molecular model, in gases

The particles are closely packed together, they occupy minimum space and are usually arranged in a regular pattern

The particles occur in clusters with molecules slightly farther apart

The molecule are very fast apart and occupy all the space made available

The particle vibrate about fixed positions and are held together by the strong intermolecular bonds between them

Answer Details

According to the kinetic molecular model, in gases, the molecules are very fast apart and occupy all the space made available. This means that gas molecules are in constant random motion and they move freely in all directions without any regular arrangement. They collide with each other and with the walls of the container, exerting pressure. The temperature of the gas is related to the average kinetic energy of the gas molecules. The higher the temperature, the faster the gas molecules move, and the higher the kinetic energy.

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Thermal Expansion

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Question 39 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 40 Report

In a slide wire bridge, the balance is obtained at a point 25cm from one end of wire 1m long. The resistance to be tested is connected to that end and a standard resistance of $3.6\,\Omega$ is connected to the other end of the wire. Determine the value of the unknown resistance

3.2

Ω

1.4

Ω

3.21

Ω

1.2

Ω

Answer Details

$\frac{R}{3.6} = \frac{75}{25} = \frac{1}{3}$

3R = 3.6

R = 1.2 $Ω$

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