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

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

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

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

can be converted into thin sheets

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

In the molecular explanation, heat is transferred by the

free electron

free atoms

free molecules

free solids

Answer Details

- Conduction is explained in terms of the free electrons
- Convection is explained in terms of the movement of the fluid involved
- Radiation is explained in terms of invisible electromagnetic waves.

Read lesson note on Thermal Expansion (JAMB)

Thermal Expansion

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Question 2 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 3 Report

When two objects A and B are supplied with the same quantity of heat, the temperature change in A is obtained to be twice that of B. The mass of P is half that of Q. The ratio of the specific heat capacity of A to B is

1 : 4

4 : 1

1 : 1

2 : 1

Answer Details

θA = 2θ $_{B}$ ,

m

_{A}

=

12

m

_{B}

H = MCθ
m $_{A}$ c $_{A}$ θ $_{A}$ = m $_{B}$ c $_{B}$ θ $_{B}$
( 1/2 m $_{B}$ )C $_{A}$ (2θ $_{B}$ ) = m $_{B}$ c $_{B}$ θ $_{B}$

C

_{A}

C

_{B}

=

11

⇒ 1 : 1

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 4 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 5 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 6 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 7 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.

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

Structure Of The Atom (Nigeria Only)

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Question 8 Report

Efficiency of conduction in liquids and gases compared to solids is

less efficient than solid

more efficient than solids

equally efficient to solids

efficiently may vary

Answer Details

The efficiency of conduction in liquids and gases compared to solids is generally less efficient. This means that solids are better conductors of heat and electricity than liquids and gases. This is because the particles in solids are closely packed and are tightly bound to one another, allowing heat and electricity to flow easily through the material. On the other hand, the particles in liquids and gases are more spread out and less tightly bound, making it more difficult for heat and electricity to flow through these materials. However, it is important to note that the efficiency of conduction can vary depending on the specific liquid or gas and the specific solid being compared. Some liquids and gases may have properties that make them better conductors than certain solids, but this is not a general rule.

View Answer

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 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 11 Report

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

the heat energy is quickly conducted away

the heat capacity has become very large as the substance melts

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

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

Answer Details

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because all the heat is used to break the bonds holding the molecules of the solid together

Read lesson note on Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 12 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 13 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 14 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}

Read lesson note on Pressure (JAMB)

Read lesson note on Motion (WAEC)

Pressure

Motion

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Question 15 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 16 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 17 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 18 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 19 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 20 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 21 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 22 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

Read lesson note on Capacitors (JAMB)

Capacitors

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Question 23 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 $Ω$

View Answer

Question 24 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.

Read lesson note on Gravitational Field (JAMB)

Gravitational Field

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Question 25 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.

View Answer

Question 26 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.

View Answer

Question 27 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 28 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 29 Report

The Earth's magnetic equator passes through Jos in Nigeria. At Jos, the

angle of variation is zero

magnetic declination is 90

angle of dip is zero

horizontal component at the Earth's field is zero

Answer Details

The Earth has a magnetic field that is generated by the movement of molten iron in its core. The magnetic field has different properties at different locations on the Earth's surface. The magnetic equator is an imaginary line on the Earth's surface where the inclination or tilt of the Earth's magnetic field is zero, meaning that the magnetic field lines are parallel to the Earth's surface. At Jos, Nigeria, the Earth's magnetic equator passes through, which means that the angle of inclination or dip of the Earth's magnetic field is zero. Therefore, the correct answer is that the angle of dip is zero. This means that a magnetic needle suspended by a thread or placed on a horizontal surface would remain horizontal and not point downwards or upwards, as it would at other locations on the Earth's surface. This makes Jos an important location for studying the Earth's magnetic field and for conducting experiments related to magnetism.

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

Electromagnetic Field (Part 2)

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Question 30 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 31 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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Question 32 Report

Heat may be transferred by conduction, convention and radiation. By which of these methods does heat travel through vacuum?

Conduction only

Convection only

Radiation only

All these methods

Answer Details

Heat can be transferred by conduction, convection, and radiation. Conduction is the transfer of heat through a material by the movement of heat-carrying particles, such as atoms or molecules, from one part of the material to another. This method of heat transfer is not possible in a vacuum, as there are no particles present to carry heat. Convection is the transfer of heat by the movement of a fluid, such as air or water. This method of heat transfer is also not possible in a vacuum, as there are no fluids present to carry heat. Radiation is the transfer of heat through electromagnetic waves, such as light or infrared radiation. This method of heat transfer does not require any material or fluid medium, and can therefore occur in a vacuum. Therefore, the answer is "Radiation only".

Read lesson note on Heat Transfer (JAMB)

Heat Transfer

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Question 33 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

Read lesson note on Pressure (JAMB)

Pressure

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Question 34 Report

The conductivity of gases at low pressure can be termed as

I. hot cathode emission

II. thermo ionic emission

III. cold cathode emission

IV. Field emission

I and II

II and III

III and IV

IV and V

Answer Details

As conduction of gases is at low pressure and high voltage, called field or cold cathode emission.

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

Properties Of Waves: Reflection, Refraction, Diffraction

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Question 35 Report

When the downward current flows in a straight vertical conductor, the direction of its magnetic field at a point due north of the wire is

Upward

North

South

West

Answer Details

At a point due N of the wire, the field is due east, at a point due S of the wire, the field is due west.

View Answer

Question 36 Report

When blue and green colours of light are mixed, the resultant colour is

cyan

magenta

black

yellow

Answer Details

Cyan is a bluish-green colour

Read lesson note on Light Waves (WAEC)

Light Waves

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Question 37 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 38 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 39 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)

Read lesson note on Measurements And Units (JAMB)

Simple Machines

Measurements And Units

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Question 40 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.

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