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Vraag 1 Verslag
In which of the points labelled A, B, C, D and E on the conductor shown would electric charge tend to concentrate most
Antwoorddetails
- 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.
Vraag 2 Verslag
Any line or section taken through an advancing wave in which all the particles are in the same phase is called the
Antwoorddetails
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.
Vraag 3 Verslag
Calculate the velocity ratio of a screw jack of pitch 0.2cm if the length of the tommy bar is 23cm
Antwoorddetails
P = 0.2cm, L = r = 23cm
VR | = | 2?rP | = | 2?LP | = | 2?×230.2 | = | 230? |
Vraag 4 Verslag
A man on a bench will exert the greatest pressure on the bench when he
Antwoorddetails
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.
Vraag 5 Verslag
Which of these is observed when air is pumped out of a discharge tube without lowering its pressure
Antwoorddetails
Conduction takes places in gases when air is pumped out of a discharged tube under reduced pressure.
Vraag 6 Verslag
Workdone on an object to bring it to a certain point in space is called
Antwoorddetails
The work done on an object to bring it to a certain point in space is called "Potential Energy". Potential energy is a form of energy that an object possesses due to its position relative to other objects. When an object is lifted or moved to a higher point against gravity, work is done on it, and this work is stored as potential energy. The potential energy of an object is directly proportional to its height and mass. It can be converted into other forms of energy, such as kinetic energy, when the object is released or allowed to move freely. Therefore, potential energy is a type of stored energy that an object has due to its position, and it can be released to do work.
Vraag 7 Verslag
A supply of 400V is connected across capacitors of 3μf and 6μf in series. Calculate the charge
Antwoorddetails
CT | = | C1 × C2 C1 + C2 |
= | 3 × 63 + 6 |
= 189
= 2μf
Q = CV
⇒ 2 × 10−6
× 400
⇒ 800 × 10−6
C = 8 × 10−4
C
Vraag 8 Verslag
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
Antwoorddetails
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.
Vraag 9 Verslag
If the time of flight is 96seconds, calculate the horizontal range through the point of projection.
Antwoorddetails
Time of flight, T = 96s
R = (Ucosθ) *time* T = 640 × 96 = 61,440m
Vraag 10 Verslag
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
Antwoorddetails
As conduction of gases is at low pressure and high voltage, called field or cold cathode emission.
Vraag 11 Verslag
A vibrator causes water ripples to travel across the surface of a tank. The wave travels 50cm in 2s and the distance between successive crests is 5cm. Calculate the frequency of the vibrator
Antwoorddetails
The frequency of the vibrator can be calculated using the formula: frequency = speed / wavelength where speed is the speed of the wave, and wavelength is the distance between successive crests. In this case, we are given that the wave travels 50cm in 2s, which means the speed of the wave is: speed = distance / time = 50cm / 2s = 25cm/s We are also given that the distance between successive crests is 5cm, which is the wavelength. Therefore, the frequency of the vibrator is: frequency = speed / wavelength = 25cm/s / 5cm = 5Hz So the correct answer is 5Hz.
Vraag 12 Verslag
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
Antwoorddetails
v | = | dt | or | v | α | d |
d = x, v = 4m/s
d = 2x, v = ? (girl and image)
v | = | 2 × 4x | = | 8 | ms |
Vraag 13 Verslag
The angular dispersion of a prism depends on
Antwoorddetails
Dispersion is due to different refractive indices speeds and wavelengths.
Vraag 14 Verslag
During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because
Antwoorddetails
When a solid is heated to its melting point, the heat supplied is used to overcome the intermolecular forces holding the molecules in a fixed position, resulting in the breaking of these bonds. As a result, the solid transforms into a liquid without any change in temperature. This is because the heat energy supplied is used in breaking the bonds between molecules rather than increasing the kinetic energy of the molecules, which is what causes an increase in temperature. Therefore, the correct option is: "all the heat is used to break the bonds holding the molecules of the solid together."
Vraag 15 Verslag
- angle of dip is zero at the magnetic equator
- angle of variation is the same as angle of declination.
Antwoorddetails
- angle of dip is zero at the magnetic equator
- angle of variation is the same as angle of declination.
Vraag 16 Verslag
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 3.6Ω is connected to the other end of the wire. Determine the value of the unknown resistance
Antwoorddetails
R3.6=7525=13
3R = 3.6
R = 1.2Ω
Vraag 17 Verslag
Efficiency of conduction in liquids and gases compared to solids is
Antwoorddetails
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.
Vraag 18 Verslag
Which of the following statement about the electromagnet shown above is correct?
Antwoorddetails
A - B = S - N.
Also, starting end of the current is south while terminating end is North.
Vraag 19 Verslag
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
Antwoorddetails
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.
Vraag 20 Verslag
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
Antwoorddetails
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.
Vraag 21 Verslag
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
(ρm = 13.6g/cm3 ρ = 0.00013g/cm3 )
Antwoorddetails
ρm
hm
= ρa
ha
13.68(760 - p) × 10−3
= 13 × 10−5
(20 × 103
)
760 | - | p | = | 13 × 10−5 × 20 × 103 13.68 × 10−3 | = | 19.00 | × | 101 |
760 - p = 190
p = 760 - 190 = 570mmHg
Vraag 22 Verslag
One newton × One meter equals?
Antwoorddetails
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.
Vraag 23 Verslag
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?
Antwoorddetails
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.
Vraag 24 Verslag
An a.c of 1A at a frequency of 800 cycles per second flows through a coil, the inductance of which is 2.5mH and the resistance of which is 5Ω. What is the power absorbed in the Coil?
Antwoorddetails
I = 1A, F = 800 cycles/s = 800Hz
R = 5Ω, L = 2.5mH
P = I2
R = I2
× 5 = 5W
Vraag 25 Verslag
The point at which the molecules of a loaded wire begin to slide across each other resulting in a rapid increase in extension is
Antwoorddetails
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.
Vraag 26 Verslag
The equilibrium position of objects in any field corresponds to situation of
Antwoorddetails
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".
Vraag 27 Verslag
During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because
Antwoorddetails
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
Vraag 28 Verslag
The following are parts of the eye
I. Retina
II. Pupil
III. Iris
The correct equivalent in the camera in the same order are
Antwoorddetails
- retina is similar to film
- pupil is similar to aperture
- iris is similar to diaphragm
Vraag 29 Verslag
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?
Antwoorddetails
f1 | = | f(v - vo )v - vs | = | 1200(340 - 15)340 - 20 | = | 1.22KHz |
Vraag 30 Verslag
In the molecular explanation, heat is transferred by the
Antwoorddetails
- 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.
Vraag 31 Verslag
"Sum of all forces acting on a body is zero." This condition represents equilibrium'
Antwoorddetails
First condition
Vraag 32 Verslag
The mass of a nucleus is the
Antwoorddetails
The mass of a nucleus is the total number of its protons and neutrons. The protons and neutrons are the subatomic particles that make up the nucleus of an atom. The mass of an atom is mostly concentrated in its nucleus, and the electrons orbiting the nucleus have a much smaller mass. Therefore, the mass of an atom is mostly determined by the number of protons and neutrons in its nucleus. The number of protons determines the element, and the number of neutrons can vary, resulting in isotopes of that element.
Vraag 33 Verslag
An alternating current can induce voltage because it has
Antwoorddetails
An alternating current can induce voltage because it has a varying magnetic field. An alternating current (AC) is an electrical current that periodically reverses direction, unlike direct current (DC), which flows in one direction. When an AC current flows through a wire, it generates a magnetic field that changes direction with the current. As the current alternates, the magnetic field expands and contracts, inducing an electromotive force (EMF) in any nearby conductor or coil of wire. This phenomenon is known as electromagnetic induction, and it is the basis for the operation of many electrical devices, such as generators and transformers. The induced voltage depends on the strength and rate of change of the magnetic field and the number of turns in the coil. In summary, an alternating current can induce voltage because it creates a varying magnetic field, which in turn generates an electromotive force in nearby conductors or coils of wire, according to the principle of electromagnetic induction.
Vraag 34 Verslag
Electrons were discovered by
Antwoorddetails
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.
Vraag 35 Verslag
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.
Antwoorddetails
From two parts 20m apart
a = 10m, x = 6m, A = 5
V = ω√A2−X2
= 5√102−62
= 40m/s
Vraag 36 Verslag
The pin-hole camera produces a less sharply defined image when the
Antwoorddetails
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.
Vraag 37 Verslag
Water and Kerosine are drawn respectively into the two limbs of a Hare's apparatus. The destiny of water is 1.0gcm−3 and the density of kerosine is 0.80gcm−3 . If the height of the water column is 20.0cm, calculate the height of the kerosine column.
Antwoorddetails
Devices with different liquids
d1
h1
= d2
h2
1 × 20 = 0.8 × h
h | = | 200.8 | = | 25cm |
Vraag 38 Verslag
The value of T in the figure above is
Antwoorddetails
Tsin30 + Tsin30 =40
2Tsin30 = 40
Tsin30 = 40/2 = 20
T(12 ) = 20
T = 20 x 2 = 40N
Vraag 39 Verslag
Radio waves belongs to the class of ware whose velocity is about
Antwoorddetails
Radio waves belong to the class of waves whose velocity is approximately 3 x 10^8 m/s. This velocity is commonly denoted as the speed of light, which is the speed at which all electromagnetic waves, including radio waves, travel in a vacuum. This constant velocity is one of the fundamental principles of physics and is important in understanding the behavior and properties of light and other electromagnetic waves. The speed of light is incredibly fast, and it's difficult for us to imagine just how fast it is. To put it into perspective, light can travel around the Earth's equator almost 7.5 times in just one second. This high speed is essential for radio communication, as it enables radio waves to travel long distances in a short amount of time, allowing us to communicate with people and devices far away from us.
Vraag 40 Verslag
Which of the following media allow the transmission of sound waves through them?
I. air
II. liquid
III. solids
Antwoorddetails
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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