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Pregunta 1 Informe
The average translational kinetic energy of gas molecules depends on
Detalles de la respuesta
The average translational kinetic energy of gas molecules is directly related to the temperature of the gas. This relationship is based on the principles of kinetic molecular theory, which explains the behavior of gas molecules in terms of their motion.
Let's break this down simply:
1. Temperature and Kinetic Energy:
The average translational kinetic energy of gas molecules is given by the equation:
\( KE_{avg} = \frac{3}{2} k_B T \)
where \( KE_{avg} \) is the average translational kinetic energy, \( k_B \) is the Boltzmann constant, and \( T \) is the absolute temperature in Kelvin. This formula shows that the kinetic energy is directly proportional to the temperature.
2. What This Means:
As the temperature of a gas increases, the molecules move faster, which increases their translational kinetic energy. Conversely, as the temperature decreases, the molecules slow down, resulting in lower kinetic energy.
It is important to note that this relation is independent of the pressure and the number of moles of the gas. While pressure and the number of moles do affect the overall behavior of a gas, they do not directly influence the average translational kinetic energy of individual molecules.
Therefore, the correct explanation is that the average translational kinetic energy of gas molecules depends on temperature only.
Pregunta 2 Informe
Which of these gas laws is equivalent to workdone
Detalles de la respuesta
To understand which of these gas laws is equivalent to work done, we must first understand the basic concept of work in the context of gases. For gases, work is done when there is a change in volume under pressure, typically expressed as W = P ΔV, where W is work, P is pressure, and ΔV is the change in volume.
Let's consider the given gas laws:
Among these, Boyle's law relates directly to work done because it involves a change in volume at constant temperature, implying that work occurs as a gas expands or compresses. The equation P₁V₁ = P₂V₂ is foundational for calculating work done in reversible processes, which aligns with the expression for work done on a gas, W = P ΔV. Thus, **Boyle's law** is most directly connected to the concept of work done on a gas.
Pregunta 3 Informe
Detalles de la respuesta
To solve this problem, we need to understand the relationship between pressure, volume, and temperature of a gas. The relevant law here is the **Combined Gas Law**, which is expressed as:
(P1 * V1) / T1 = (P2 * V2) / T2
Where:
In the given problem:
Applying the Combined Gas Law:
(P1 * V1) / 300 = (2 * P1 * V2) / 400
Simplifying this equation:
V1/300 = 2V2/400
Multiply both sides by 400 to clear the fraction:
400 * V1 / 300 = 2 * V2
Which further simplifies to:
(4/3) * V1 = 2 * V2
Dividing both sides by 2:
(2/3) * V1 = V2
This shows that the final volume, V2, is **2/3 of the initial volume, V1**. Therefore, the volume of the gas will **decrease by 1/3**.
Pregunta 4 Informe
The equivalent capacitance of the capacitors in the circuit above
Detalles de la respuesta
apacitance in parallel = one at the top + one under = 2C
The two in the middle are in series = C2
The equivalent capacitance of the capacitors in the circuit above = C2 + 2C = 52 C
Pregunta 5 Informe
The simple form of the lead acid accumulator often has a negative pole of
Detalles de la respuesta
The simple form of the lead acid accumulator often has a negative pole of lead plate. In a lead-acid battery, the key components include two electrodes and an electrolyte. The **negative pole**, also known as the cathode during discharge, is typically made of **lead (Pb)**, which is in the form of a **lead plate**. When the battery is in use or discharging, this lead reacts with sulphuric acid (the electrolyte) to create lead sulfate.
To break it down further:
Thus, by analyzing the composition and reactions within a lead-acid battery, it is clear that the **negative pole** is made from a **lead plate**.
Pregunta 6 Informe
Bilateral symmetry,cylindrical bodies and double openings are characteristic features of
Detalles de la respuesta
Bilateral symmetry, cylindrical bodies, and double openings are characteristic features of nematodes. Nematodes, also known as roundworms, have a body structure that is symmetric along a single plane, which results in two mirror-image halves, thus exhibiting bilateral symmetry.
Furthermore, they usually have a cylindrical body shape, which means their bodies are long and narrow like a cylinder and taper at both ends. This shape helps them move through their environment easily. Additionally, nematodes have a complete digestive system with two openings: a mouth and an anus. This means that food enters through the mouth, gets digested, and waste exits through the anus.
In contrast, organisms like hydra, protozoa, and protists possess different anatomical features. Hydras, for example, typically show radial symmetry, and protozoa and protists generally do not have a well-defined body shape or bilateral symmetry as seen in nematodes. Therefore, the description fits nematodes best.
Pregunta 7 Informe
The friction due to air mass can be reduced by
Detalles de la respuesta
Friction due to air mass, also known as air resistance or drag, can be reduced by a concept called **streamlining**.
**Streamlining** refers to the shaping of an object in such a way that it allows air to flow smoothly around it, minimizing turbulence and reducing drag. When air flows smoothly over an object without much disturbance, there is less resistance, and the object can move more easily through the air.
Think of it like how a bullet or a fast-moving car is designed. They have a sleek, smooth shape that cuts through the air with minimal effort. This principle is applied in designing cars, airplanes, and even boats to enhance their efficiency and speed by reducing the friction with the air or water they move through.
Pregunta 8 Informe
The energy stored in the above capacitor is
Detalles de la respuesta
The energy stored in the capacitor = 12 q2C
Where C = 2F, q = 3C
= 12 322 = 94 = 2.25J
Pregunta 9 Informe
A solid cube of aluminum is 1.5cm on each edge. The density of aluminum is 2700kgm−1 . Find the mass of the cube.
Detalles de la respuesta
The mass of an object can be calculated using the formula:
Mass = Density × Volume
In this case, we need to find the mass of a solid cube of aluminum. Given:
First, we need to calculate the volume of the cube. The volume V of a cube with edge length a is given by:
V = a3
Substitute the edge length:
V = (1.5 cm)3 = 1.5 × 1.5 × 1.5 cm3 = 3.375 cm3
Since the density is given in kg/m3, we should convert the volume from cm3 to m3. There are 1,000,000 cm3 in 1 m3, so:
Volume in m3 = 3.375 cm3 × (1 m3/1,000,000 cm3) = 3.375 × 10-6 m3
Now, use the mass formula:
Mass = Density × Volume
Mass = 2700 kg/m3 × 3.375 × 10-6 m3
This equals:
Mass = 9.1125 × 10-3 kg
Convert kg to grams (since 1 kg = 1000 g):
Mass = 9.1125 grams
So, the mass of the cube is approximately 9.1 g. Thus, the correct answer is 9.1 g.
Pregunta 10 Informe
In a Hare's apparatus, the height of water and a liquid X are 0.3m and 0.5m respectively. The relative density of x is?
Detalles de la respuesta
For Hare's apparatus
Relative density = hwhl
Given: height of liquid = 0.5cm, height of water = 0.3cm
Relative density = 0.30.5 = 0.6
Pregunta 11 Informe
Mouth part adapted for piercing and sucking is found in
Detalles de la respuesta
The mouthpart adapted for piercing and sucking is found in the mosquito. Mosquitoes have a specialized mouth structure called a proboscis. This proboscis is long and slender, allowing mosquitoes to puncture the skin of their hosts and suck blood. The proboscis is a complex structure that contains several needle-like parts that make the piercing and sucking process efficient and effective.
Pregunta 12 Informe
In electrolysis, when same quantity of electricity is passed through different electrolytes, mass of substances deposited is proportional to
Detalles de la respuesta
In electrolysis, when the same quantity of electricity is passed through different electrolytes, the mass of substances deposited is proportional to their chemical equivalent. The reason for this lies in Faraday's laws of electrolysis. Faraday's second law states that the amounts of different substances deposited or liberated by the same quantity of electricity are proportional to their chemical equivalents.
Chemical equivalent refers to a measure of a substance's ability to react or be deposited during electrolysis, and it is calculated as the molar mass divided by valency (n). This is why it is sometimes also referred to as equivalent weight.
In essence, for a given charge (equal number of electrons or electricity), a substance with a lower chemical equivalent will deposit more mass because it requires fewer electrons to undergo the chemical change.
Pregunta 13 Informe
When a bus is accelerating, it must be
Detalles de la respuesta
When a bus is accelerating, it is primarily changing its velocity. This is because velocity is a vector quantity, which means it includes both the speed and the direction of the object's movement. Acceleration refers to any change in this velocity. Therefore, the bus could be increasing its speed, decreasing its speed (which is also known as deceleration), or changing its direction. All these aspects involve a change in velocity.
Let's break it down further:
Changing its Speed: If the bus is speeding up or slowing down, it results in a change in the magnitude of its velocity, contributing to acceleration.
Changing its Direction: Even if the bus maintains a constant speed, if it changes direction (like taking a turn), its velocity is altered because direction is a part of velocity. This results in acceleration.
Changing its Position: While a change in position happens during acceleration, it is not the defining feature of acceleration. An object can change its position even if it is moving with constant velocity and not accelerating.
So, the key component here for acceleration is the change in velocity, which encompasses changes in speed, direction, or both.
Pregunta 14 Informe
Electrolysis can be investigated using
Detalles de la respuesta
When investigating electrolysis, the most relevant instrument from the list provided is the Voltameter. This is because the voltameter is specifically designed to measure the amount of substance that is deposited or consumed at electrodes during the electrolysis of an electrolyte. It functions based on the chemical change associated with the electric current passing through the electrolyte.
Here is a simple explanation of how electrolysis works and why a voltameter is useful:
Electrolysis is the process of using electricity to cause a chemical reaction, which is usually a decomposition reaction. This involves passing an electric current through an electrolyte (a substance containing free ions). These ions migrate towards electrodes, resulting in chemical changes. The key aspect to measure during electrolysis is the amount of material (e.g., metal or gas) that is deposited at the electrodes.
The Voltameter helps in understanding electrolysis because:
Voltmeter, Ammeter, and Galvanometer are not used primarily for investigating electrolysis:
Pregunta 15 Informe
The web-feet of frogs and toads is basically for
Detalles de la respuesta
The web-feet of frogs and toads is primarily for swimming. These webbed feet act like paddles, allowing the frog or toad to move efficiently through the water. When the animal spreads its toes, the webbing provides a larger surface area, which gives better propulsion in the water. This adaptation is essential, as many species of frogs and toads spend a significant amount of their time in aquatic environments where efficient swimming helps them in searching for food, escaping predators, and traveling from one place to another. In essence, the webbed feet are a vital feature for their aquatic lifestyle.
Pregunta 16 Informe
Calculate the quantity of heat for copper rod whose thermal capacity is 400Jk−1 for a temperature change of 60ºC to 80ºC
Detalles de la respuesta
To calculate the quantity of heat absorbed or released by a substance, we can use the formula:
Q = C × ΔT
where:
Given:
First, calculate the change in temperature:
ΔT = Final temperature - Initial temperature = 80°C - 60°C = 20°C
Now, substitute the values into the formula to find the quantity of heat:
Q = 400 J/°C × 20°C
Calculate the answer:
Q = 8000 J
Since the options provided are in kilojoules (KJ), we need to convert joules (J) to kilojoules (1 KJ = 1000 J):
Q = 8000 J ÷ 1000 = 8 KJ
Therefore, the quantity of heat for the copper rod, given the specified conditions, is 8 KJ.
Pregunta 17 Informe
What will be the weight of a man of mass 60kg standing in a lift if the lift is descending vertically at 3ms2 ?
Detalles de la respuesta
To find the apparent weight of a man of mass 60 kg standing in a descending lift, we first need to understand the concept of apparent weight. Apparent weight is the force that the man feels as his weight due to the reaction of the lift floor on him. When the lift accelerates, the apparent weight changes from his actual weight.
In this case, the lift is descending with a constant velocity of 3 m/s2. Since the acceleration is downward, it means the lift is accelerating negatively compared to an upward acceleration.
The formula to find the apparent weight (Wapparent) when in a lift is:
Wapparent = m(g - a)
Where:
Substituting these values into the formula, we get:
Wapparent = 60 (9.8 - 3)
Calculating further:
Wapparent = 60 × 6.8
Wapparent = 408 N
The closest option to 408 N in the answers provided is 420 N. Therefore, the correct answer is 420 N.
Pregunta 18 Informe
A thick glass tumbler cracks when boiling water is poured into it because
Detalles de la respuesta
When boiling water is poured into a thick glass tumbler, the inner surface of the glass is suddenly exposed to a much higher temperature compared to the outer surface. Glass is a poor conductor of heat, which means it does not transfer heat quickly. As a result, the inside of the tumbler becomes hot and attempts to **expand quickly**, while the outside remains cooler and does not expand at the same rate.
**This uneven expansion** creates tension between the inner and outer layers of the glass. The inner surface tries to expand but is constrained by the cooler, rigid outer surface, which isn't expanding as much or as quickly. This stress and tension can lead to cracking.
Therefore, the correct reason a thick glass tumbler cracks when boiling water is poured into it is because **the inside expands more rapidly than the outside.**
Pregunta 19 Informe
Using the diagram above, the effective force pushing it forward at an angle 60º is
Detalles de la respuesta
To determine the effective force pushing the object forward at an angle of 60º, we need to resolve the given force into its components. Specifically, we are interested in the horizontal component of the force, as this is the part that effectively pushes the object forward.
The general formula to calculate the horizontal component of a force (Fx) when the force is applied at an angle (θ) is:
Fx = F * cos(θ)
Where:
Assuming the magnitude of the force applied (F) is 50N, then the effective forward force can be calculated as follows:
Fx = 50N * cos(60º)
Using the trigonometric value:
cos(60º) = 0.5
Therefore:
Fx = 50N * 0.5
Fx = 25N
Hence, the effective force pushing it forward at an angle of 60º is 25.00N. Therefore, the correct answer is 25.00N.
Pregunta 20 Informe
A medium texture soil with high organic matter is
Detalles de la respuesta
A medium texture soil with high organic matter is best described as loamy soil. Here's why:
Loamy soil is a type of soil that is characterized by a balanced mixture of sand, silt, and clay particles. Because of this blend, loamy soil is not too coarse like sandy soil, nor is it too compact and dense like clay soil, making it a medium texture.
Moreover, loamy soil is renowned for its high organic matter content. This means that it contains a significant amount of decomposed plant and animal residues, which enrich the soil and provide essential nutrients for plant growth. This high organic content enhances the soil's fertility and structure, enabling it to retain moisture yet drain well, making it ideal for farming and gardening.
In conclusion, due to its balanced texture and richness in organic matter, loamy soil is the best fit for a medium-textured soil with high organic matter.
Pregunta 21 Informe
One of these is not the use of an electroscope
Detalles de la respuesta
Measuring ionization current in air:
This is typically not a function of an electroscope. While it can detect charge, it does not measure ionization currents, which require specialized equipment like an ionization chamber.
Pregunta 22 Informe
Calculate the value of electric field intensity due to a charge of 4μC if the force due to the charge is 8N
Detalles de la respuesta
To calculate the electric field intensity due to a charge, we need to use the formula:
Electric Field Intensity (E) = Force (F) / Charge (q)
In this problem, we are given that the force (F) is 8 Newtons (N) and the charge (q) is 4 microcoulombs (μC). First, we need to convert the charge from microcoulombs to coulombs:
1 microcoulomb (μC) = 1 x 10-6 coulombs (C)
Therefore, 4 μC = 4 x 10-6 C.
Now we can use the formula to find the electric field intensity:
E = F / q
E = 8 N / (4 x 10-6 C)
E = 8 / 4 x 106
E = 2 x 106
Thus, the value of the electric field intensity is 2 x 106 N/C.
Pregunta 23 Informe
5 X 10−3 kg of liquid at its boiling point is evaporated in 20s by the heat generated by a resistor of 2Ω when a current of 10A is used. The specific latent heat of vaporization of the liquid is
Detalles de la respuesta
To solve this problem, we need to calculate the specific latent heat of vaporization of the liquid. The specific latent heat of vaporization, denoted as \(L\), is defined as the amount of heat required to convert 1 kilogram of a liquid into a gas at constant temperature and pressure. The formula for specific latent heat of vaporization is given by:
L = \(\frac{Q}{m}\)
Where:
First, we need to calculate the total heat energy \(Q\) generated by the resistor. The heat produced by an electrical resistor can be calculated using the formula:
Q = I^2Rt
Where:
Given:
Substituting these values into the formula for Q:
Q = (10^2) * 2 * 20 = 100 * 2 * 20 = 4000 J
Now that we have the total heat energy supplied, let's calculate the specific latent heat of vaporization:
Given that the mass \(m\) of the liquid evaporated is \(5 \times 10^{-3}\) kg, we can substitute the values into the formula for \(L\):
L = \(\frac{4000}{5 \times 10^{-3}} = \frac{4000}{0.005} = 800,000 J/kg\)
Therefore, the specific latent heat of vaporization of the liquid is 8.0 x 105 J/kg.
Pregunta 24 Informe
The energy in a moving car is an example of
Detalles de la respuesta
The energy in a moving car is an example of kinetic energy.
To explain simply, **energy** is the ability to do **work** or cause **change**. There are different forms of energy, and **kinetic energy** is one of them. It is defined as the energy possessed by an object due to its motion.
When a car is moving, it possesses **kinetic energy** because its components are in **motion**. This motion energy allows the car to do tasks, such as transporting people or goods from one place to another. The faster the car moves, the greater its **kinetic energy**, and thus it can make a larger impact or do more work.
In contrast, energy forms like **mechanical energy** is a combination of both kinetic and potential energy; **electrical energy** is associated with electrical charge movement, while **potential energy** is related to the position or condition of an object (like a car parked on a hill). Therefore, the specific type of energy from a moving car is **kinetic energy**.
Pregunta 25 Informe
Calculate the magnetic force on an electron in a magnetic field of flux density 10T, with a velocity of 3 x 107 m/s at 60º to the magnetic field (e = 1.6 x 10−19 C)
Detalles de la respuesta
The magnetic force on an electron in a magnetic field (F) = q v Bsinθ
B = 10T, q = 3 x 107 m/, θ = 60º and q = 1.6 x 10−19 C
F = 1.6 x 10−19 x 3 x 107 x 10 x sin 60º ≊ 4.162 × 10−11 N
Pregunta 26 Informe
Calculate the upthrust on a spherical ball of volume 4.2 x 10−4 m3 when totally immersed in a liquid of density 1028kgm−3
Detalles de la respuesta
Upthrust(Force) = volume of object x density of liquid x g = V x ρ x g
U = 4.2 x 10−4 x 1028 x 10 ≊ 4.3N
Pregunta 27 Informe
If a body in linear motion changes from point P to Q, the motion is
Detalles de la respuesta
When a body moves in a straight line from one point, such as point P, to another point, such as point Q, the motion is called Translational Motion. This kind of motion refers to an object moving along a path in which every part of the object takes the same path as a reference point. This means that if you follow any point on the body, it covers the same amount of distance in the same time frame as any other point.
Let's break down the other options:
In conclusion, since the body is moving from point P to point Q along a straight line, it exhibits Translational Motion.
Pregunta 28 Informe
I clear II sharp III poor IV dark
Which of the above happens when the hole of a pinhole camera is diminished?
Detalles de la respuesta
A pinhole camera is a simple camera device that uses a tiny hole to project an inverted image of the scene in front of it onto a surface at the back of the camera. When you diminish the hole of a pinhole camera, meaning you make the hole smaller, a few effects occur on the resulting image. Here’s what happens:
Therefore, reducing the size of the pinhole in a pinhole camera results in the image becoming both darker and sharper.
Answer: II only (The image becomes sharper.)
Pregunta 29 Informe
Detalles de la respuesta
When you insert a sheet of an insulating material between the plates of an air capacitor, the capacitance will increase.
Here's why:
C = ε₀ * (εr) * (A/d)
Therefore, inserting an insulating material as a dielectric enhances the capacitor's ability to store charge, ultimately resulting in an increase in capacitance.
Pregunta 30 Informe
The mechanical advantage of the machine shown above
Detalles de la respuesta
Mechanical advantage of a machine = LOADEFFORT
In this case of a wedge, we can consider the dimensions given:
Load distance (height of the machine): 15 cm
Effort distance (movement of the effort): 0.5 cm
M.A = 150.5 = 30.0
Pregunta 31 Informe
Calculate the power of an object which moves through a distance of 500cm in 1s on a frictionless surface by a horizontal force of 50N
Detalles de la respuesta
To calculate the power of an object, we need to use the formula for power in terms of work done over time. The formula is:
Power (P) = Work Done (W) / Time (t)
First, let's find the work done on the object. Work done can be calculated using the formula:
Work Done (W) = Force (F) × Distance (d)
Given:
Substituting the values into the formula for work done, we get:
Work Done (W) = 50 N × 5 m = 250 Joules
Next, we consider the time it took for the object to move this distance:
Now, substituting the work done and time into the power formula:
Power (P) = 250 Joules / 1 s = 250 Watts
Thus, the power of the object is 250 Watts.
Pregunta 32 Informe
The dimension of power is
Detalles de la respuesta
The dimension of power in physics is expressed in terms of the base units of mass (M), length (L), and time (T). Power is the rate at which work is done or energy is transferred over time, and it has the unit of watt (W) which is equivalent to one joule per second.
To derive the dimension of power:
1. Work has the dimension of energy, which is force applied over a distance. The dimension of work (or energy) is M L2 T-2 because force has the dimension M L T-2 and distance adds another L.
2. Since power is work done per unit time, you would divide the dimension of work by time (T).
Thus, the dimensional formula for power is:
M L2 T-3
Pregunta 33 Informe
One main feature of trees in the savanna habitat is the possession of
Detalles de la respuesta
The main feature of trees in the savanna habitat is the possession of thick, corky bark. The savanna is characterized by a distinct wet and dry season. During the dry season, fires are common as dry grasses and leaves become highly flammable. To adapt to this environmental condition, many trees in the savanna have developed a thick, corky bark which helps protect them against these frequent fires. This bark acts as an insulator, shielding the vital inner tissues of the tree from the heat of the flames. Additionally, this adaptation helps the trees retain moisture, which is crucial during the arid months when water is scarce.
Pregunta 34 Informe
According to kinetic theory of gases, the pressure exerted by the gas on the wall is equal
Detalles de la respuesta
According to the kinetic theory of gases, the pressure exerted by a gas on the walls of its container relates to the behavior and movement of its molecules. To understand how this pressure forms, let's explore the following essential concepts.
Molecules in a gas move rapidly and randomly in all directions. When these molecules collide with the walls of their container, they exert force due to the change in momentum during these collisions. The frequency and force of these collisions contribute directly to the pressure experienced by the container walls.
The **pressure** exerted by the gas can be described in terms of the rate of change of momentum imparted by the walls per second per unit area. This means that pressure is determined by considering how fast and how much the momentum of the gas molecules changes when they bounce off the container's walls, spread over a specific area and over time. In simpler terms, the faster and more frequently molecules hit the walls, and the higher their change in momentum, the greater the pressure is.
This explanation can be directly associated with the statement: "rate of change of momentum imparted by the walls per second per unit area", which accurately describes the concept of pressure in the context of the kinetic theory of gases.
Pregunta 35 Informe
A sonometer's fundamental note is 50Hz, what is the new frequency when the tension is four times the original?
Detalles de la respuesta
To solve this problem, we need to understand the relationship between tension and frequency in a sonometer wire. The frequency of a vibrating string, such as one in a sonometer, is directly proportional to the square root of the tension in the string. Mathematically, this relationship is expressed as:
f ∝ √T
Where f is the frequency and T is the tension. In the given problem, the original frequency is 50 Hz, and the tension is increased to four times its original value. Let's analyze how this change in tension affects the frequency:
- Original tension = T
- New tension = 4T
Substitute the new tension into the formula:
f_new = 50 Hz × √(4T/T)
Simplify the equation:
f_new = 50 Hz × √4
f_new = 50 Hz × 2
f_new = 100 Hz
Thus, when the tension is four times the original tension, the new frequency of the sonometer's fundamental note becomes 100 Hz.
Pregunta 36 Informe
A red shirt under a red light appears pale because red
Detalles de la respuesta
To understand why a red shirt appears pale under red light, we need to consider how colors are perceived. A shirt's color is due to the light it reflects. A red shirt reflects red light and absorbs other colors. This is why it looks red under normal white light, which is made up of many colors including red.
When you place a red shirt under red light, the only available light to reflect is red. Since the shirt is already designed to reflect red light, it reflects the red light and appears its vivid color. However, it might appear brighter or paler since no other colors are present to contrast against the red.
Therefore, the best explanation is that the red shirt absorbs other colours and reflects red.
Pregunta 37 Informe
The dimension of young's modulus,E is given by
Detalles de la respuesta
Young's modulus, denoted by E, is a measure of the stiffness of a solid material. It is defined as the ratio of stress to strain in a material that is behaving elastically. Stress is the force applied per unit area, and strain is the deformation experienced by the material in response to the applied stress.
Let's break down the dimensions for Young's modulus:
Stress: Stress is defined as force per unit area. Thus, the dimension of stress can be expressed as:
Stress = Force / Area
The dimension of force is given by mass × acceleration, i.e., Force = MLT-2 (where M is mass, L is length, and T is time).
The dimension of area is length × length = L2.
Therefore, the dimension of stress is:
Stress = (MLT-2) / (L2) = ML-1T-2
Strain: Strain is the ratio of the change in length to the original length and is dimensionless because it is a ratio of two lengths.
Thus, the dimension of strain is simply 1 (dimensionless).
Since Young's modulus is the ratio of stress to strain, its dimension is the same as that of stress. Therefore, the dimension of Young’s modulus E is:
ML-1T-2
Pregunta 38 Informe
I It wets glass
II It needs to be coloured
III It has a low density
Water is not suitable for use as a thermometric liquid because
Detalles de la respuesta
Water is not suitable for use as a thermometric liquid because:
a) It wets glass: This can cause issues with reading the level of the liquid.
b) It needs to be coloured: Water is typically clear, making it difficult to see the level without coloring.
c) It has a low density: This can affect the sensitivity and accuracy of the thermometer.
Pregunta 39 Informe
Use the diagram above to answer the question that follows
The diagram above is
Detalles de la respuesta
The diagram in the image represents the urinary system, as indicated by the correct answer. The urinary system includes the kidneys, ureters, bladder, and urethra, which are responsible for filtering blood and excreting waste in the form of urine.
Kidneys – Filter waste and excess fluids from the blood to form urine.
Ureters – Tubes that carry urine from the kidneys to the bladder.
Urinary Bladder – Stores urine before it is expelled from the body.
Urethra – A tube that allows urine to exit the body.
This system plays a crucial role in maintaining the body's fluid balance and removing waste products.
Pregunta 40 Informe
Use the diagram above to answer the question that follows
The zone labelled II is called
Detalles de la respuesta
The zone labelled II is called the littoral zone.
To explain: The littoral zone is a part of a body of water that is close to the shore. It is typically characterized by abundant sunlight and nutrient availability, making it a highly productive area for aquatic plants and animals. This zone supports various forms of life such as algae, small fish, and invertebrates. The key feature of the littoral zone is its proximity to the shoreline, where sunlight can penetrate to the bottom, allowing for photosynthesis to occur.
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