WAEC SSCE - Physics - 2001 (Objective)

Question 1 Report

If the frequency of the tuning fork at resonance is 256Hz, calculate the frequency of vibration of the wire when the tension in he wire is increased to 196N

130.6Hz

182.9Hz

358.4Hz

501.8Hz

Answer Details

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Scalars And Vectors

Thermal Expansion

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Question 2 Report

a beam PQ pivoted at P carries a load of 80N as shown above. Calculate the effort E, required to keep it horizontal. [neglect the weight of the beam]

32.0N

26.7N

16.0N

13.3N

Answer Details

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Question 3 Report

Surface waves travelling in deep water at 15ms^-1 are incident at a shallow water boundary. If the angles of incidence and refraction are 45^o and 30^o respectively. Calculate the speed of the waves in shallow water

8.1ms^-1

10.0ms^-1

10.6ms^-1

22.5ms^-1

Answer Details

When surface waves travelling in deep water meet a shallow water boundary, they experience a change in speed and direction. This is known as refraction. The speed of the waves is dependent on the medium they are travelling through, so when they enter shallow water, their speed will change. We can use Snell's law, which states that the ratio of the sines of the angles of incidence and refraction is equal to the ratio of the velocities in the two media. In this case, we have: \begin{align*} \frac{\sin i}{\sin r} &= \frac{v_i}{v_r} \\ \frac{\sin 45}{\sin 30} &= \frac{15}{v_r} \\ \frac{\sqrt{2}}{0.5} &= \frac{15}{v_r} \\ v_r &= \frac{15}{\frac{\sqrt{2}}{0.5}} \\ v_r &= 10.6\text{ms}^{-1} \end{align*} Therefore, the speed of the waves in shallow water is approximately 10.6ms^-1. The correct option is (c) 10.6ms^-1.

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Motion

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Question 4 Report

A nitrogen nucleus bombarded with an alpha particle produces an oxygen nucleus and a proton. The nuclear reaction for this process is \(^4_2H + ^{14}_2N \to ^{17}_{8}O + ^1_1H + Q\). Which of the following statements about the reaction is not correct?

the bombardment results into a nucleus with greater proton number

it is an induced nuclear reaction

it is a natural radioactive decay

the sum of the final nucleon numbers

Answer Details

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Electromagnetic Field (Part 2)

Electromagnetic Field (Part 1)

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Question 5 Report

Which of the following physical processes cannot be explained by the molecular theory of matter?

evaporation

thermal conduction

radiation of heat

convectional current of fliuds

Answer Details

The physical processes of evaporation, thermal conduction, radiation of heat, and convectional current of fluids can all be explained by the molecular theory of matter. The theory explains that all matter is made up of tiny particles (atoms or molecules) which are constantly in motion. The motion of these particles can cause heat transfer through conduction, convection, and radiation. Evaporation is a process where some of the particles at the surface of a liquid have enough energy to escape and become a gas. Therefore, all the options listed can be explained by the molecular theory of matter.

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Heat Transfer

Electrical Energy And Power

Thermal Expansion

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Question 6 Report

The volume of an ideal gas at a pressure of 77cmHg and temperature 60^oC is 24cm³. If the temperature and pressure are increased to 98^oC
and 81cmhg respectively, calculate the new volume of the gas

411.5cm³

267.1cm³

254.2cm³

112.7cm³

Answer Details

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Gas Laws

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Question 7 Report

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

angle of variation is zero

magnetic declination is 90^o

angle of dip is zero

horizontal component of the Earth's magnetic field is zero

Answer Details

The Earth's magnetic field has a north and south pole, and it is tilted with respect to the Earth's rotational axis. This means that at different points on the Earth's surface, the magnetic field has different characteristics. The magnetic equator is an imaginary line that circles the Earth, and it is the point where the magnetic field is horizontal. At Jos in Nigeria, the magnetic equator passes through, and this means that the magnetic field is horizontal at this point. Therefore, the angle of dip (the angle between the magnetic field lines and the Earth's surface) is zero.

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Description Property Of Fields

Magnetic Field (Part 1)

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Question 8 Report

Electrical resistance is a property of an electrical energy to be converted into

mechanical energy

heat energy

magnetic energy

chemical energy

Answer Details

Electrical resistance is a property of a material to oppose the flow of electrical current through it. When electrical current flows through a conductor, some of the electrical energy is converted into other forms of energy. One of the forms of energy that can be generated is heat energy, which is the result of collisions between the electrons and the atoms in the material. This is known as Joule heating, and the amount of heat generated is proportional to the resistance of the material and the square of the current flowing through it. Therefore, when electrical energy flows through a material with resistance, some of the energy is converted into heat energy due to the resistance of the material.

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Electrostatics

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Question 9 Report

The apparent weight of a body fully immersed in water is 32N and its weight in air is 96N. Calculate the volume of the body. [Density of water = 1000kgm^-3, g = 10ms^-2]

8.9 x 10^-3m³

6.4 x 10^-3m³

3.2 x 10^-3m³

3.0 x 10^-3m³

Answer Details

The apparent weight of a body in a fluid is equal to the weight of the fluid displaced by the body. Using this principle, we can calculate the volume of the body as follows: Let V be the volume of the body Density of water = 1000kgm^-3 Weight of the body in air = 96N Weight of the body in water = 32N We know that: Weight of the body in air - Weight of the body in water = Upthrust = Weight of the water displaced Therefore, 96N - 32N = Weight of the water displaced 64N = Weight of the water displaced Weight of water displaced = Volume of body x Density of water x g 64N = V x 1000kgm^-3 x 10ms^-2 V = 64N / (1000kgm^-3 x 10ms^-2) V = 6.4 x 10^-3m³ Therefore, the volume of the body is 6.4 x 10^-3m³. Answer is correct.

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Measurements And Units

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Question 10 Report

Humidity is used to describe the amount of

air in water vapour

cloud available in the atmosphere

air in equal volume of cloud

water vapour in the amosphere

Answer Details

Humidity is used to describe the amount of water vapour present in the atmosphere. It is the measure of the water vapour content in the air, which can affect how comfortable we feel in a particular environment. Humidity can be measured in various ways, including absolute humidity, relative humidity, and specific humidity. Knowing the humidity level is important for a range of applications, from weather forecasting to indoor comfort control.

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Temperature And Its Measurement

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Question 11 Report

An incident ray is reflected normally by a plane mirror onto a screen where it forms a bright spot. The mirror and screen are parallel and 1m apart. If the mirror is rotated through 5^o, calculate the displacement of the spot

8.7cm

10.0cm

15.4cm

17.6cm

Answer Details

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Scalars And Vectors

Electrostatics

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Question 12 Report

The time rate of change of momentum is

impulse

force

power

pressure

Answer Details

The time rate of change of momentum is called "force". Force is a vector quantity that causes an object to accelerate or change its velocity. When a force acts on an object for a certain amount of time, it produces a change in the object's momentum, which is called impulse. Therefore, force can also be defined as the rate of change of momentum, that is, the amount of impulse produced per unit of time.

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Newton’s Laws Of Motion

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Question 13 Report

A block weighing 15N rests on a flat surface and a horizontal force of 3N is exerted on it. Determine the friction force on the block

0.3N

0.5N

3.0N

5.0N

Answer Details

The force exerted on the block is 3N, and the block is at rest, meaning that the force of friction is equal in magnitude and opposite in direction to the applied force. Therefore, the friction force on the block is 3N. Answer: 3.0N

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Question 14 Report

The amplitude of the motion of a body performing simple harmonic motion decreases with time because

friction force dissipate the energy of motion

the frequency of oscillation varies with time

the period of oscillation varies with time

energy is supplied by some external agency

Answer Details

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Simple Harmonic Motion

Work, Energy And Power

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Question 15 Report

The diagram above shows the wire of a sonometer box set into resonance by a vibrating tuning fork of frequency f, when the wire is stretched by a tension T, the resonating length of the wire is I while the wavelength of the sound produced is \(\lambda\). Which of the following statements about the frequency of vibration of the wire is not correct?

proportional to the mass per unit length of the wire

equal to the frequency of the tuning fork

inversely proportional to the length of the wire

proportional to the sqare root of the tension

Answer Details

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Scalars And Vectors

Measurements And Units

Concepts Of Matter

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Question 16 Report

Three identical lamps each power 100W are connected in parallel across a potential difference of 250V. Calculate the current in the circuit

7.5A

2.5A

1.2A

0.8A

Answer Details

When lamps are connected in parallel, each lamp has the same voltage across it. Therefore, the potential difference across each of the three lamps is 250V. The power of each lamp is given as 100W. We know that power (P) is equal to voltage (V) multiplied by current (I), i.e., P = VI. Therefore, the current through each lamp can be calculated as I = P/V = 100/250 = 0.4 A. Since the lamps are connected in parallel, the total current in the circuit is the sum of the currents through each lamp. Hence, the total current in the circuit is 3 times the current through one lamp, which is 3 x 0.4 A = 1.2 A. Therefore, the correct option is 1.2A.

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Current Electricity

Simple A.C Circuits

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Question 17 Report

Which of the following statements about pressure is not correct? pressure

increases with an increase in surface area

decreases with an increase in surface area

increases with a decrease in surface area

increases with an increase in the applied force

Answer Details

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Pressure

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Question 18 Report

stationary and lonitudinal

stationary and mechanical

mechanical and longitudinal

progessive and transverse

Answer Details

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Electrostatics

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Question 19 Report

Electrons passing through crystals are diffracted because they

are repelled by the atoms in the crystal

are attracted by the atoms in the crystals

possess wave properties

are particles

Answer Details

Electrons, which are usually considered as particles, can also exhibit wave-like properties, a concept known as wave-particle duality. When electrons are passed through crystals, their wave-like nature allows them to diffract, meaning they bend and scatter as they encounter the atoms in the crystal. This is similar to the way light diffracts when it passes through a narrow opening or encounters an obstacle. Therefore, the correct answer is that electrons passing through crystals are diffracted because they possess wave properties.

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Wave-particle Paradox

Structure Of The Atom (Nigeria Only)

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Question 20 Report

What is the effective capacitance in the circuit?

2\(\mu F\)

6\(\mu F\)

18\(\mu F\)

216\(\mu F\)

Answer Details

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Capacitors

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Question 21 Report

Which of the following statements about elastic collision is correct?

momentum is lost due to the sound produced

loss of momentim is equal to loss in kinetic energy

both kinetic energy and momentum are conserved

kinetic energy is lost while momentum is conserved

Answer Details

In an elastic collision, both kinetic energy and momentum are conserved. This means that the total kinetic energy before the collision is equal to the total kinetic energy after the collision, and the total momentum before the collision is equal to the total momentum after the collision. There is no loss of kinetic energy or momentum in an elastic collision. Therefore, the statement "both kinetic energy and momentum are conserved" is correct. The other statements are incorrect as they imply a loss of either kinetic energy or momentum in an elastic collision, which is not the case.

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Elasticity

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Question 22 Report

As the plates of a charged variable capacitor are moved closer together, the potential difference between them

increased

decrease

remains the same

is doubled

Answer Details

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Electrostatics

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Question 23 Report

An electric bulb is rated 60W, 220V. Calculate the resistance of its filament when it is operating normally

296.7\(\Omega\)

400.0\(\Omega\)

512.2\(\Omega\)

806.7\(\Omega\)

Answer Details

The power of an electrical appliance can be calculated by the formula P = V\(^2\)/R, where P is the power in watts, V is the voltage in volts, and R is the resistance in ohms. In this case, the bulb is rated 60W and 220V. So, we can rearrange the formula to find the resistance: R = V\(^2\)/P. Substituting the values gives us: R = 220\(^2\)/60. Evaluating this expression gives us: R = 806.7\(\Omega\). Therefore, the resistance of the filament when the bulb is operating normally is 806.7\(\Omega\). Note: It is important to remember that the actual resistance of the filament may vary due to factors such as temperature, age, and manufacturing tolerances.

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Current Electricity

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Question 24 Report

The amplitude of a particle executing simple harmonic motion in 5cm while its angular frequency is 10 rad s^-1. calculate the magnitude of the maximum acceleration of the particle

0.25ms^-2

0.50ms^-2

2.00ms^-2

5.00ms^-2

Answer Details

The maximum acceleration of a particle in simple harmonic motion is given by the product of the square of the angular frequency and the displacement of the particle from the equilibrium position. That is, a_max = -ω²A Where, A is the amplitude of the particle, and ω is the angular frequency. Substituting the given values, we get: a_max = - (10 rad/s)² x 0.05 m a_max = - 5 m/s² or 5 ms^-2 Since the maximum acceleration is a scalar quantity, we take its magnitude, which is simply 5 ms^-2. Therefore, the correct option is 5.00ms^-2.

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Simple Harmonic Motion

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Question 25 Report

A given mass of an ideal gas has a pressure of 500Nm^-2 at -13^oC. If its volume remains constant. Calculate its pressure at 247^oC.

25Nm^-2

50Nm^-2

500Nm^-2

1000Nm^-2

Answer Details

The pressure, volume, and temperature of an ideal gas are related by the ideal gas law, which is given by: P V = n R T where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the absolute temperature. If the volume of the gas remains constant, then the ideal gas law becomes: P = n R T / V Since the mass of the gas is constant, the number of moles n is also constant. Therefore, we can write: P/T = constant This means that the pressure of the gas is directly proportional to its temperature, when the volume is constant. To solve the problem, we can use the above formula to find the constant, and then use it to find the pressure at the new temperature: P1 / T1 = P2 / T2 where P1 is the initial pressure, T1 is the initial temperature, P2 is the final pressure, and T2 is the final temperature. Converting the temperatures to kelvin scale: T1 = 273 - 13 = 260 K T2 = 273 + 247 = 520 K Substituting the values: 500 / 260 = P2 / 520 Solving for P2: P2 = (500 / 260) x 520 = 1000 Nm^-2 Therefore, the pressure of the gas at the new temperature is 1000 Nm^-2. The correct option is: 1000Nm^-2.

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Gas Laws

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Question 26 Report

What is the total energy stored by the capacitors?

2.0 x 10^-4J

1.0 x 10^-4J

9.0 x 10^-2J

1.0 x 10^-2J

Answer Details

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Capacitors

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Question 27 Report

Which of the following statements about magnetic lines of force is not correct?

a magnnetic line of force is an imaginary line which the north pole of a magnet would describe if it is free to moves

magnetic lines of force do not cross one another

magnetic lines of force are closely packed together at neutral point

the presence of magnetic lines of force in a region indicates the presence of a magnetic field

Answer Details

The correct option is "magnetic lines of force are closely packed together at neutral point". This statement is incorrect because neutral points are regions where the magnetic field is zero, and hence, there are no magnetic lines of force in these regions. Magnetic lines of force are an imaginary concept used to represent the direction and intensity of magnetic fields. They are assumed to be continuous and form closed loops, and are said to originate from the north pole and terminate at the south pole of a magnet. They also represent the path along which a free north pole would move in the presence of a magnetic field. Magnetic lines of force do not cross one another, and the presence of magnetic lines of force in a region indicates the presence of a magnetic field.

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Magnets And Magnetic Fields

Magnetic Field (Part 1)

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Question 28 Report

A piece of cloth appears green in sunlight. When held in red light, it will appear

green

blue

red

black

Answer Details

When an object appears a certain color, it is because it reflects that particular color of light and absorbs all other colors. Therefore, if a piece of cloth appears green in sunlight, it means that it reflects green light and absorbs all other colors. When the same piece of cloth is held in red light, it will appear black. This is because the red light being shone on the cloth contains only red light waves, and the cloth will absorb all the red light, as it does not reflect red light. Therefore, it appears black, as there is no reflected color for our eyes to see.

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Gas Laws

Light Energy

Reflection Of Light At Plane And Curved Surfaces

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Question 29 Report

Which of the following equations represents the distance x, travelled by a body moving on a straight road with a constant speed? [The other symbol have their usual meanings]

x = Ut + \(\frac{1}{2}t^2\)

x = Ut

x = \(\frac{V^2 - U^2}{2a}\)

x = -\(\frac{1}{2} at^2\)

Answer Details

The equation that represents the distance x, travelled by a body moving on a straight road with a constant speed is "x = Ut". In this equation, "U" represents the initial velocity of the body and "t" represents the time taken to cover the distance "x". Since the body is moving with a constant speed, its velocity remains the same throughout the journey and can be represented by "U". Therefore, the distance covered by the body can be calculated by multiplying the velocity "U" with the time taken "t", which is given by the equation "x = Ut". The other given equations represent the distance covered by a body in different scenarios like constant acceleration, initial velocity with constant acceleration, etc.

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Motion

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Question 30 Report

Which of the following statements about sound is correct?

when sound travels from air to a denser medium, it is refracted away from the normal at the point of incidence

sound travels faster in air than in water

the wavelength of sound changes when it travels from to water

the frequency of it travels from air to water

Answer Details

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Question 31 Report

A resistance thermometer has a resistance of 20\(\Omega\) at 0^oC and 85\(\Omega\) at 100^oC. If its resistance is 52\(\Omega\)in a medium, calculate the corresponding temperature

49.2^oC

60.6^oC

80.0^oC

84.7^oC

Answer Details

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Temperature And Its Measurement

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Question 32 Report

The material used for constructing the core of an electromagnet is

iron

carbon

copper

steel

Answer Details

The material used for constructing the core of an electromagnet is iron. An electromagnet is made by wrapping a coil of wire around a ferromagnetic core. When electric current flows through the wire, it creates a magnetic field around the wire. The ferromagnetic core helps to increase the strength of the magnetic field created by the current flowing through the wire. Iron is a good material for the core of an electromagnet because it is a ferromagnetic material that is easily magnetized and demagnetized. It also has a high magnetic permeability, which means it can conduct magnetic flux effectively.

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Electromagnetic Field (Part 2)

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Question 33 Report

In the circuit diagram above. Calculate the energy stored in the inductor at resonance

0.100J

0.050J

0.010J

0.005J

Answer Details

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Capacitors

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Question 34 Report

The magnitude of the gravitational force between two particles 0.10m apart is 10N. If the distance between them is increased to 0.20m, calculate the magnitude of the new force

40.0N

20.0N

5.0N

2.5N

Answer Details

The gravitational force between two particles is given by the formula F = Gm₁m₂/r², where G is the gravitational constant, m₁ and m₂ are the masses of the particles, and r is the distance between them. In this case, the distance between the particles is initially 0.10m and the force is 10N. If the distance is increased to 0.20m, we can use the formula to calculate the new force. Let's assume that the masses of the particles remain constant. The distance between them is doubled, so the new distance is 2r = 0.20m. Plugging this into the formula and solving for the new force, we get: F' = Gm₁m₂/(2r)² = Gm₁m₂/4r² Since the masses of the particles and the gravitational constant are constants, the only thing that has changed is the distance between the particles. Therefore, the new force is proportional to 1/r². Since r has doubled, the new force will be (1/2)² = 1/4 of the original force. So, the new force is: F' = (1/4)F = (1/4)10N = 2.5N Therefore, the magnitude of the new force is 2.5N. Option (C) is the correct answer.

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Gravitational Field

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Question 35 Report

The amount of heat given out or absorbed when a substance changes its state at a constant temperature is known as

latent heat

heat capacity

specific latent heat

specific heat capacity

Answer Details

The amount of heat given out or absorbed when a substance changes its state at a constant temperature is known as latent heat. This means that even though the temperature remains constant during the change of state, heat is still being absorbed or released. For example, when ice is melted into water or water is evaporated into steam, there is no change in temperature, but heat is still absorbed by the substance during the change of state. The latent heat is specific to the substance and the change of state, and can be calculated by multiplying the mass of the substance by the specific latent heat of the substance for the particular change of state.

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Quantity Of Heat

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Question 36 Report

Convex spherical mirrors are preferred to plane mirrors as driving mirrors because

the image produce is upright and clearly visible

it provides a wider field of view

the image produce is errect and diminished

the image produced is not laterally inverted

Answer Details

Convex spherical mirrors are preferred to plane mirrors as driving mirrors because they provide a wider field of view. Convex mirrors are curved outward and the reflected light rays diverge, resulting in a smaller image that appears farther away. This makes it easier for drivers to see objects behind them and in their blind spots. The wider field of view provided by convex mirrors is particularly useful for large vehicles such as buses and trucks, which have larger blind spots than smaller cars.

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Question 37 Report

Calculate the reactance of the inductor in the circuit diagram shown above [\(\pi = \frac{22}{7}\)]

132\(\Omega\)

214\(\Omega\)

264\(\Omega\)

269\(\Omega\)

Answer Details

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Capacitors

Simple A.C Circuits

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Question 38 Report

A spring balance,which is suspended from the roof of a lift, carries a mass of 1kg at its free end. If the lift accelerates upwards at 2.5ms^-2, determine the reading on the spring balance. [g = 10ms^-2]

24.0N

12.5N

7.5N

4.0N

Answer Details

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Scalars And Vectors

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Question 39 Report

An object weight 10N immersed in a liquid displaces a quantity of the liquid. If the liquid displaced weighs 6N, determine the upthrust of the object

20N

10N

Answer Details

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Gravitational Field

Fluid At Rest

Work, Energy And Power

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Question 40 Report

A simple machine with an efficiency of 75% lifts a load of 5000N when a force of 500N is applied to it. Calculate the velocity ratio of the machine

10.0

13.3

17.5

25.0

Answer Details

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Simple Machines

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Question 41 Report

A screw jack with a Tommy bar of length 12cm is used to raise a car through a vertical height of 25cm by turning the Tommy bar through 50 revolutions. Calculate the approximate velocity ratio of the jack [\(\pi = 3.142\)]

151

Answer Details

A screw jack is a simple machine used to lift heavy loads with little effort. The velocity ratio of a screw jack is defined as the ratio of the distance moved by the effort (Tommy bar) to the distance moved by the load (car). In this case, the car is raised through a vertical height of 25cm by turning the Tommy bar through 50 revolutions. The distance moved by the effort is the circumference of the circle traced out by the end of the Tommy bar, which is given by: circumference = 2πr = 2 x 3.142 x 0.12m = 0.754m (approx.) Since the Tommy bar is turned through 50 revolutions, the total distance moved by the effort is: distance moved by effort = 0.754m x 50 = 37.7m (approx.) Therefore, the velocity ratio is: velocity ratio = distance moved by effort / distance moved by load = 37.7m / 0.25m = 150.8 (approx.) So the approximate velocity ratio of the jack is 151, which is closest to.

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Simple Machines

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Question 42 Report

Which of the following physical qualities affects the saturated vapour pressure of a liquid ?

temperature

volume

mass

density

Answer Details

The physical quality that affects the saturated vapour pressure of a liquid is temperature. Saturated vapour pressure is the pressure exerted by the vapour present in a system at equilibrium with its condensed phase, usually a liquid. As temperature increases, the average kinetic energy of the liquid molecules increases, causing more molecules to escape from the liquid phase and enter the gas phase. This leads to an increase in the number of gas molecules, which in turn results in an increase in pressure. As a result, the saturated vapour pressure of a liquid increases with increasing temperature, and decreases with decreasing temperature. Therefore, temperature is the correct answer. The other options - volume, mass, and density - do not directly affect the saturated vapour pressure of a liquid.

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Temperature And Its Measurement

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Question 43 Report

An object is placed 20cm from a lens. If an image is formed on a screen 260cm away from the lens, calculate the magnification of the image

Answer Details

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Structure Of Matter And Kinetic Theory

Electrostatics

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Question 44 Report

Production of x-ray tube begins with

photo electric emission

collision of electrons

thermionic emission

field emission of electrons

Answer Details

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Structure Of The Atom (Nigeria Only)

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Question 45 Report

Dispersion of white light by a glass prism occurs because

white light consist of a mixture of seven different colour

the refractive index of glass is different from each constituent colour of white light

the speed of each colour of light in the glass is proportional to the refractive index of glass for each colour

the speed of each colour of light in the glass is proportional to the angle of refraction in he prism

Answer Details

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Refraction Of Light Through Plane And Curved Surfaces

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