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

Ripple in a power supply unit is caused by

using an alternating current source

The mass of a nucleus is the

total number of its proton and neutrons

total number of its protons and electrons

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

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

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

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 2 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 3 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 4 Report

When water is boiling, it

gets hotter

increase is mass

decreases in mass

changes to steam

Answer Details

When water is boiling, it changes from a liquid state to a gaseous state called steam. This happens when the water is heated to its boiling point, which is when it reaches a temperature of 100 degrees Celsius (212 degrees Fahrenheit) at sea level. As the water is heated, it absorbs energy and the molecules start to move faster and faster, eventually reaching a point where they escape into the air as steam. The temperature of the water during boiling does not change, as all the energy is being used to break the bonds between the water molecules rather than increasing the temperature. Therefore, the options "gets hotter," "increase in mass," and "decreases in mass" are not correct when describing what happens when water is boiling.

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Question 5 Report

The limiting frictional force between two surface depends on

I. the normal reaction between the surfaces

II. the area of surface in contact

III. the relative velocity between the surfaces

IV. the nature of the surface

I only

I and IV only

II only

III only

Answer Details

The correct answer is "I and IV only". The limiting frictional force between two surfaces depends on the normal reaction between the surfaces (I) and the nature of the surface (IV). The normal reaction is the force that the surfaces exert on each other perpendicular to the plane of contact. The greater the normal reaction, the greater the frictional force that can be applied before motion occurs. The nature of the surface is determined by factors such as roughness, hardness, and texture, which can affect the frictional force. The area of surface in contact (II) does not directly affect the limiting frictional force, although it can affect the force required to initiate motion. For example, if the area of contact is small, the pressure between the surfaces will be higher, making it harder to initiate motion. The relative velocity between the surfaces (III) also does not directly affect the limiting frictional force, although it can affect the force required to maintain motion. If the surfaces are already in motion, a lower force may be required to keep them moving than to initiate motion. In summary, the limiting frictional force between two surfaces depends primarily on the normal reaction and the nature of the surface, and is not directly affected by the area of contact or the relative velocity between the surfaces.

Read lesson note on Friction (JAMB)

Friction

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Question 6 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 7 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 8 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

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Simple Harmonic Motion

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Question 9 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 10 Report

Gases conduct electricity under

high pressure and high voltage

low pressure and low voltage

normal pressure and low voltage

low pressure and high voltage

Answer Details

Gases conduct electricity under low pressure and high voltage

Read lesson note on Gas Laws (JAMB)

Gas Laws

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Question 11 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 12 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 13 Report

A coil X is moved quickly away from the end Y of a stationary metal bar and a current then flows in X as shown above.

Then

the bar is not a magnet

Y is a north pole

Y is a South pole

Y repels coil X

Answer Details

N - S magnet is moved towards a coil production clockwise direction of current in the coil.
- This is the same as a coil moved away from S-N (Y - North pole)

Read lesson note on Electromagnetic Field (Part 2) (WAEC)

Read lesson note on Electromagnetic Field (Part 1) (WAEC)

Electromagnetic Field (Part 2)

Electromagnetic Field (Part 1)

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Question 14 Report

The equilibrium position of objects in any field corresponds to situation of

equipotential energy

maximum potential energy

minimum potential energy

maximum kinetic energy

Answer Details

The equilibrium position of an object in any field corresponds to the situation of minimum potential energy. This means that at the equilibrium position, the object has the lowest possible potential energy within the field. In other words, the forces acting on the object are balanced, and the object is not being pushed or pulled in any direction. Therefore, the object will remain at rest at the equilibrium position unless it is acted upon by an external force. Of the options given, the correct answer is "minimum potential energy".

Read lesson note on Gravitational Field (WAEC)

Read lesson note on Measurements And Units (JAMB)

Gravitational Field

Measurements And Units

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Question 15 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 16 Report

Any line or section taken through an advancing wave in which all the particles are in the same phase is called the

wavelength

wave coast

wave trough

wave front

Answer Details

The answer is: wave front. A wave front is any imaginary line or surface that connects all points of a wave that are in the same phase, meaning they are at the same point in their cycle. In other words, it is a line or surface that separates the points of a wave that are in-phase from those that are out-of-phase. For example, consider the ripples on the surface of a pond when a stone is thrown in. The wave fronts are the concentric circles that emanate from the point where the stone entered the water. All points along a given circle are in-phase, meaning the water molecules at those points are at the same point in their oscillation cycle. In summary, a wave front is a line or surface that separates points in a wave that are in-phase from those that are out-of-phase.

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Production And Propagation Of Waves

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Question 17 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 18 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 19 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 20 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 21 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 22 Report

The pitch of a screw jack is 0.45cm and the arm is 60cm long. If the efficiency of the Jack is 75/π %, calculate the mechanical advantage.

400

300

200

150

Answer Details

P = 0.45cm, L = 60cm, Eff = 75/π%

VR

(Screw

system)

=

2πrP

=

2πLP

M.A

=

Eff% × VR100

=

75π

×

1100

×

2π × 600.45

=

75 × 800300

=

200

Read lesson note on Simple Machines (JAMB)

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Simple Machines

Measurements And Units

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Question 23 Report

A single force which produces the same effect as a set of forces acting together at a point is known as the

component

equilibrant

resultant

resistant

Answer Details

The single force which produces the same effect as a set of forces acting together at a point is known as the "resultant". In other words, the resultant is the net force that results from combining all the individual forces acting on an object. It represents the combined effect of all the forces acting on the object and is the force that would produce the same motion as the original set of forces acting together. Therefore, when solving problems in physics, it is often useful to find the resultant force in order to determine the overall effect of multiple forces on an object.

Read lesson note on Scalars And Vectors (WAEC)

Read lesson note on Simple A.C Circuits (JAMB)

Read lesson note on Equilibrium Of Forces (WAEC)

Scalars And Vectors

Simple A.C Circuits

Equilibrium Of Forces

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Question 24 Report

One newton × One meter equals?

One water

One Joule

One ampere

One kilogram

Answer Details

One newton times one meter is equal to one Joule. A newton is the unit of measurement for force, and a meter is the unit of measurement for distance. When force is applied over a distance, work is done, which is measured in Joules. Therefore, one newton multiplied by one meter results in one Joule of work done. The other options listed (one water, one ampere, one kilogram) are not correct units of measurement for this calculation.

Read lesson note on Scalars And Vectors (JAMB)

Scalars And Vectors

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Question 25 Report

A safety precaution designed to prolong the life of a lead acid accumulator is

By topping up the cells with concentrated acid

The use of naked flame when charging the battery

Keeping the specific gravity of the electrolyte within specified range

By connecting wires to the terminals directly when testing the level of charging

Answer Details

- Topping is done with distilled water
- Naked flame should be avoided when charging the battery
- Direct connection of wires to the terminals should be avoided.

View Answer

Question 26 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 27 Report

A cone is in unstable equilibrium has its potential energy

decreased

increased

unchanged

oscillating

Answer Details

In unstable equilibrium, potential energy decreases as the height decreases.

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 28 Report

Which of the following media allow the transmission of sound waves through them?

I. air

II. liquid

III. solids

I and II only

I and III only

II and III only

I, II and III

Answer Details

Sound waves are disturbances in a medium that propagate through the medium and transfer energy from one point to another. The transmission of sound waves depends on the physical properties of the medium, including its elasticity and density. Air (Option I) is a gas that is compressible and has a relatively low density, which makes it an excellent medium for transmitting sound waves. Liquids (Option II) are also able to transmit sound waves, although the speed of sound in liquids is slower than in gases because liquids are more dense and less compressible. Solids (Option III) are able to transmit sound waves as well, but their density and elasticity make them more rigid, which means that sound waves in solids tend to be transmitted as elastic waves or mechanical waves, rather than as acoustic waves. Therefore, the correct answer is "I, II, and III".

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Sound Waves

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Question 29 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)

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Newton’s Laws Of Motion

Scalars And Vectors

Equilibrium Of Forces

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Question 30 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 31 Report

Which of the following readings cannot be determined with a meter rule?

2.56cm

2.25cm

2.50cm

2.05cm

Answer Details

Meter rule has a reading accuracy of 0.5mm or 0.05cm, thus measurement is M ± 0.05cm i.e 2.00, 2.05, 2.50, 2.55 etc.
The reading that cannot be read is 2.56cm.

Read lesson note on Measurements And Units (JAMB)

Measurements And Units

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Question 32 Report

The limiting frictional force between two surfaces depends on

I. the normal reaction between the surfaces

II. the area of surface in contact

III. the relative velocity between the surfaces

IV. the nature of the surfaces

I only

II only

III only

I and IV only

Answer Details

- Friction depends on the nature of the surfaces in contact
- Solid friction is independent of the area of the surfaces in contact and the relative velocity between the surfaces.

Read lesson note on Friction (JAMB)

Friction

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Question 33 Report

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

pin-hole is larger

illumination is less

screen is further from the pin-hole

object is further from the pin-hole

Answer Details

The pin-hole camera produces a less sharply defined image when the pin-hole is larger. A pin-hole camera works by allowing light to pass through a small hole (the pin-hole) and project an inverted image of the outside world onto a screen or surface located behind the hole. The smaller the pin-hole, the sharper the resulting image, as light passing through a smaller hole produces less diffraction or spreading out of the light. When the pin-hole is larger, more light enters the camera, but the light rays also become more scattered, resulting in a less well-defined image. This is because the larger opening allows more light rays to enter at different angles, creating a wider range of paths that the light can take as it travels through the camera and onto the screen. As a result, the image is less clear and less defined, with less sharp edges and more blurring. is the correct answer because it correctly identifies the effect of a larger pin-hole on the image produced by the pin-hole camera. less illumination, would actually produce a dimmer image, but it would not affect the sharpness or definition of the image. the distance of the screen from the pin-hole, and the distance of the object from the pin-hole, would affect the size of the image and the scale of the objects, but they would not affect the sharpness or definition of the image.

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Light Energy

Structure Of The Nucleus

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Question 34 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.

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Force On A Current-Carrying Conductor In A Magnetic Field

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Question 35 Report

The following are some units

I. Ns

II. Non

III. $ \mathrm{Nm}^{-2} $

IV. $ \mathrm{J^\circ K}^{-1} $

V. $ \mathrm{JKj}^{-1} $

What are the units of latent heat?

I

II

III

V

Answer Details

Latent heat or specific latent heat = L

Heat

energy

=

mL

or

L

=

Hm

=

energymass

Read lesson note on Work, Energy & Power (JAMB)

Read lesson note on Measurements And Units (JAMB)

Work, Energy & Power

Measurements And Units

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Question 36 Report

A siren having a ring of 200 hole makes 132 rev/min. A jet of air is directed on the set of holes. Calculate the frequency and wavelength in air of the note produced (take v = 350m/s)

0.875m

0.625m

0.335m

0.125m

Answer Details

n = 200, S = 132 rev/min, v = 350m/s $^{2}$

f

=

ns

=

200

×

132

revmin

×

1min60s

=

440Hz

λ

=

vf

=

350440

=

0.875m

Read lesson note on Quantity Of Heat (JAMB)

Quantity Of Heat

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Question 37 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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Question 38 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 39 Report

A supply of 400V is connected across capacitors of 3μf and 6μf in series. Calculate the charge

8 x 10

^{- 4}

C

4 x 10

^{- 2}

C

8 x 10

^{- 3}

C

4 x 10

^{- 8}

C

Answer Details

C

_{T}

=

C

_{1}

× C

_{2}

C

_{1}

+ C

_{2}

=	3 × 63 + 6

= $\frac{18}{9}$ = 2μf
Q = CV
⇒ 2 × 10 $^{- 6}$ × 400
⇒ 800 × 10 $^{- 6}$ C = 8 × 10 $^{- 4}$ C

Read lesson note on Capacitors (JAMB)

Capacitors

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Question 40 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.

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

Structure Of The Atom (Nigeria Only)

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