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Question 1 Report
The linear expansivity of brass is 2 x 10?5
C?1
. If the volume of a piece of brass is 15.00cm at 0°C, what is the volume at 100°C
Answer Details
The linear expansivity of brass is given as 2 x 10^-5 /°C. This means that for every 1°C increase in temperature, the brass expands by 2 x 10^-5 of its original size. To find the new volume of the brass at 100°C, we need to take into account the expansion in all three dimensions (length, width, and height). Since the expansivity given is for length only, we need to find the expansivity in all three dimensions by multiplying it by 3. The expansivity in all three dimensions is: 3 x (2 x 10^-5 /°C) = 6 x 10^-5 /°C To find the new volume, we can use the formula: Vf = Vi (1 + αΔT) where Vf is the final volume, Vi is the initial volume, α is the expansivity in all three dimensions, and ΔT is the change in temperature. Plugging in the values, we get: Vf = 15.00 cm3 (1 + (6 x 10^-5 /°C) x (100°C - 0°C)) Vf = 15.09 cm3 Therefore, the volume of the brass at 100°C is 15.09 cm3.
Question 2 Report
In the diagram shown, which of the simple pendulum will resonate with P when set into oscillation?
Answer Details
Question 3 Report
A lens of focal length 15cm forms on erect image which is three times the size of the object. The distance between the object and the image is ___.
Answer Details
We can use the lens formula, 1/f = 1/v - 1/u, where f is the focal length of the lens, v is the distance between the lens and the image, and u is the distance between the lens and the object. From the problem, we know that the focal length of the lens is 15 cm, and the image is erect and three times the size of the object. This means that the image distance v is positive and the object distance u is negative (since the object is in front of the lens). Let's assume that the object distance u is -x cm, where x is a positive number. Then, the image distance v is +3x cm, since the image is three times the size of the object. Substituting these values into the lens formula, we get: 1/15 = 1/(+3x) - 1/(-x) Simplifying the right-hand side, we get: 1/15 = (1 + 3)/3x Multiplying both sides by 3x, we get: 3x/15 = 4 Simplifying, we get: x = 20 Therefore, the distance between the object and the lens is -20 cm (since it is in front of the lens), and the distance between the image and the lens is +60 cm (since it is behind the lens). The distance between the object and the image is the sum of these distances, which is: (-20) + (+60) = 40 cm Therefore, the answer is 40cm.
Question 4 Report
Which of the following diagrams represents correctly an n-p-n transistor?
i.
Answer Details
Question 5 Report
What flows to the earth by connecting the conductor to the earth?
Answer Details
When a conductor is connected to the earth, electrons flow to the earth. Electrons are negatively charged particles that are present in all conductors. When a conductor is connected to the earth, it creates a path for electrons to flow from the conductor to the earth, which helps to balance the electric potential and prevent the buildup of electric charge. This flow of electrons is known as grounding and is an important safety measure in electrical systems.
Question 6 Report
Which of the following is true of an electrical charge?
Answer Details
The correct answer is option D: "All of the above." An electrical charge refers to the presence of an excess or deficit of electrons in an atom or molecule. In this context, positive charge means a deficit of electrons, whereas negative charge means an excess of electrons. Electric current refers to the flow of charged particles, typically electrons, through a conductor. Therefore, an electric current means the movement of electrons. In summary, all of the given options are true of an electrical charge, and they all relate to the behavior of electrons in an electrically charged system.
Question 7 Report
Which of the following best describes the energy changes which take place when a steam engine drives a generator which lights a lamp?
Answer Details
The energy changes that take place when a steam engine drives a generator which lights a lamp can be described as: Heat energy from burning fuel is used to create steam in the boiler of the steam engine. This steam is then used to drive the turbine, which generates kinetic energy as it spins. The kinetic energy is transferred to the generator, which converts it into electrical energy (electricity). The electricity then flows through the wires to the lamp, where it is converted back into light energy, which is what we see. Therefore, the correct option would be: Heat ----> Kinetic ----> Electricity ----> Light
Question 8 Report
A room is heated by means of a charcoal fire, an occupants of the room standing away from the fire is warmed mainly by
Answer Details
The main way that the occupants of a room standing away from a charcoal fire are warmed is by radiation. Radiation is the transfer of heat energy through electromagnetic waves, and it can travel through empty space. In this scenario, the charcoal fire emits radiation in the form of infrared waves, which travel through the air and warm up the objects (including the occupants) in the room. Convection, on the other hand, is the transfer of heat through the movement of fluids (such as air), but in this case, the air in the room is not being actively circulated by a fan or other mechanism. Conduction involves the transfer of heat through direct contact between two objects, but the occupants are not in direct contact with the fire. Reflection refers to the bouncing of radiation off a surface, but it is not a significant factor in this scenario as most of the radiation is absorbed by the objects in the room.
Question 9 Report
A ball of mass 5.0kg hits a smooth vertical wall normally with a speed of 2ms?1
. Determine the magnitude of the resulting impulse
Answer Details
The magnitude of the resulting impulse can be calculated using the formula impulse = change in momentum. In this scenario, the ball experiences a change in velocity (speed) as it hits the wall. The ball's initial momentum is equal to its mass times its velocity, and its final momentum is zero since it comes to a stop after hitting the wall. The change in momentum is equal to the final momentum minus the initial momentum, which is equal to the negative of the initial momentum. Since the ball has a mass of 5.0 kg and a velocity of 2 m/s, its initial momentum is 5.0 kg * 2 m/s = 10.0 kg m/s. Therefore, the change in momentum is -10.0 kg m/s and the magnitude of the resulting impulse is 10.0 kg m/s, which is equal to 10.0 Ns. So, the correct answer is 10.0kgms−1.
Question 10 Report
If the fraction of the atoms of a radioactive material left after 120years is 164 , what is the half-life of the material? 164
Answer Details
The half-life of a radioactive material is the time it takes for half of the atoms in a sample to decay. The fraction of atoms left after a certain number of half-lives can be calculated using the formula: fraction left = (1/2)^(number of half-lives) Let's use this formula to solve the problem. We know that the fraction of atoms left after 120 years is 1/64, which means that: (1/2)^(number of half-lives) = 1/64 To solve for the number of half-lives, we can take the logarithm of both sides: log[(1/2)^(number of half-lives)] = log(1/64) Using the rule that log(a^b) = b*log(a), we can simplify the left side of the equation: number of half-lives * log(1/2) = log(1/64) Dividing both sides by log(1/2), we get: number of half-lives = log(1/64) / log(1/2) Using a calculator or the change of base formula, we can evaluate this expression: number of half-lives = 6 Therefore, the half-life of the material is 120/6 = 20 years.
Question 11 Report
The tendency of a body to remain at rest when a force is applied to it is called.
Answer Details
The tendency of a body to remain at rest or to continue moving with a constant velocity (in a straight line at a constant speed) when no force is acting on it is called inertia. Inertia is a property of matter, and the amount of inertia depends on the mass of an object. Inertia can also be thought of as a resistance to changes in motion, meaning that an object at rest will tend to stay at rest, and an object in motion will tend to stay in motion unless acted upon by an external force. This property of inertia is what makes it difficult to start, stop, or change the direction of motion of an object. The force required to overcome the inertia of an object depends on the mass of the object and the magnitude of the acceleration desired. Therefore, the greater the mass of an object, the greater its inertia, and the more force required to change its motion.
Question 12 Report
A positively charged rod X is brought near an uncharged metal sphere Y and is then touched by a finger with X still in place. When the finger is removed, the result is that Y has
Answer Details
Question 13 Report
A solid weighs 45N and 15N respectively in air and water. Determine the relative density of the solid
Answer Details
The relative density of a substance is defined as the ratio of its density to the density of a reference substance, usually water at 4 degrees Celsius. In this problem, we can use the principle of buoyancy to determine the density of the solid. When an object is submerged in a fluid, it experiences an upward force called the buoyant force, which is equal to the weight of the fluid displaced by the object. If the object is less dense than the fluid, it will float, and if it is more dense, it will sink. We are given that the solid weighs 15 N in water, which means it displaces 15 N of water. The weight of the water displaced is equal to the buoyant force on the solid, which is equal to the weight of the solid when it is completely submerged in water. Therefore, the weight of the solid when it is completely submerged in water is 15 N. We are also given that the weight of the solid in air is 45 N. The difference between the weight of the solid in air and water is equal to the weight of the water displaced, which is 30 N. This means that the volume of water displaced by the solid is 30/9.8 = 3.06 L (since the density of water is 1000 kg/m^3 or 9.8 N/L). The relative density of the solid is equal to its density divided by the density of water. We can find the density of the solid by dividing its weight in air by its volume: Density of solid = Weight of solid in air / Volume of solid Density of solid = 45 N / (45 N - 15 N) [since weight of displaced water is 15N] Density of solid = 45 N / 30 N Density of solid = 1.5 N/L Therefore, the relative density of the solid is: Relative density = Density of solid / Density of water Relative density = 1.5 N/L / 1000 N/L Relative density = 0.0015 So the answer is 0.33 (rounded to two decimal places).
Question 14 Report
Shadows and eclipses result from the
Answer Details
The rectilinear propagation of light means that light travels in straight lines as a wave. This can be observed in the well-defined shadows formed when an object blocks a light source and through the use of a pinhole camera.
According to Sudipa Sarkar, the formation of shadows with sharp edges demonstrates the rectilinear propagation of light, i.e. The fact that light travels in straight line. When an opaque obstacle is placed between a source of light and a screen, a shadow of the obstacle is formed on the screen. The kind of shadow depends on the size of the source of light. If it is a point source (light from a small hole), the shadow obtained is a region of total darkness, called umbra.
If an extended source of light, e.g. a bulb, is used, the umbra is surrounded by a region of partial darkness, called penumbra. The moon is seen because it reflects the sun's light. An eclipse of the moon (lunar eclipse) occurs when the earth comes between the sun and the moon and prevents some of the light from the sun from reaching the moon. In other words, the earth casts its shadow on the moon. The solar eclipse occurs when the moon comes between the sun and the earth.
Question 15 Report
The product of force and time is?
Answer Details
The product of force and time is known as impulse. Impulse can be defined as the change in momentum that an object experiences as a result of a force being applied to it over a period of time. In simpler terms, impulse is the "push" that an object receives from a force acting on it for a certain amount of time. The more force applied, or the longer the time the force is applied, the greater the impulse and the greater the change in momentum of the object. It's important to note that impulse is a vector quantity, meaning it has both magnitude and direction. Impulse is a measure of the ability of a force to cause an object to change its velocity, and can be used to explain many phenomena in physics, such as why a heavy object is harder to stop than a lighter one, or why a soccer ball changes direction when it is kicked.
Question 16 Report
The process by which protons are converted into helium atoms with a tremendous release of energy is called?
Answer Details
The process by which protons are converted into helium atoms with a tremendous release of energy is called "thermonuclear fusion". In this process, two light atomic nuclei combine to form a heavier nucleus, releasing a huge amount of energy in the form of light and heat. This is the same process that powers the sun and other stars. The high temperatures and pressures required for fusion to occur can only be achieved in stars or in controlled environments such as fusion reactors. Thermonuclear fusion is different from nuclear fission, which is the process of splitting a heavy nucleus into lighter nuclei with the release of energy. Thermionic emission and photoelectric emission are different processes that involve the emission of electrons from a material due to heating or exposure to light, respectively.
Question 17 Report
If the focal length of a camera is 20cm, the distance from the film at which the lens must be set to produce a sharp image of 100cm away is
Answer Details
F = 20cm
V = 100cm
U = ?
1U
+ 1V
= 1F
120
+ 1100
= 1F
5+1100
= 1F
F = 1006
= 16.7cm
= 17cm
Question 18 Report
The resistance of a 40W car head lamp, drawing current from a 12V battery is ____.
Answer Details
The resistance of a 40W car headlamp can be calculated using Ohm's Law, which states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points, and inversely proportional to the resistance (R) of the conductor. The equation can be written as V = IR. Since the power (P) of the headlamp is given as 40W and the voltage is 12V, we can calculate the current using the equation P = IV. Substituting I = P/V, we get I = 40/12 = 3.33A. Finally, using Ohm's Law, we can calculate the resistance as R = V/I = 12/3.33 = 3.6Ω. So, the resistance of the 40W car headlamp, drawing current from a 12V battery, is 3.6Ω.
Question 19 Report
Which of the following concepts is not an evidence of the particles nature of matter?
Answer Details
The particle nature of matter refers to the idea that matter is made up of tiny particles that are constantly moving. Diffusion, Brownian motion, and crystallization are all examples of phenomena that can be explained by the particle nature of matter. However, diffraction is not an evidence of the particle nature of matter. Diffraction is a phenomenon that occurs when waves encounter an obstacle or a slit, causing them to spread out and interfere with each other. While particles can also exhibit diffraction, this is a property of waves and is not specific to particles. In summary, diffusion, Brownian motion, and crystallization are all evidences of the particle nature of matter, but diffraction is not.
Question 20 Report
The diagram shown represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is 40, then the value of W is?
Answer Details
Let the total number of pulleys used in both the blocks be n
.
In a block-and-tackle pulley system, the velocity ratio is equal to n.
Efficiency = MAVR×100%
MA=LE,VR=n
Efficiency = LE×1n×100%
E=LEff.×n×100%
E=120N40%×6×100%
E=50N
Question 21 Report
A resistor connected to a 12V battery draws a current of 2A. The energy dispatched in the resistor in 5 minutes is ___.
Answer Details
To calculate the energy dispatched in the resistor, we need to use the formula: Energy = Power x Time Where Power is the amount of electrical power consumed by the resistor, and is equal to the product of the voltage across the resistor and the current flowing through it: Power = Voltage x Current In this case, the voltage across the resistor is 12V, and the current flowing through it is 2A. Therefore, the power consumed by the resistor is: Power = 12V x 2A = 24W Now, we can substitute this value of power along with the given time of 5 minutes into the formula for energy: Energy = 24W x 5min x 60s/min = 7,200J Therefore, the energy dispatched in the resistor in 5 minutes is 7,200J. is the correct answer.
Question 22 Report
In the diagram given the hanging mass m2 is adjusted until m1 is on the verge of sliding. The coefficient of static
Answer Details
I think the correct option is C (m2m1 ). The coefficient of friction is a ratio of two forces and hence g will cancel out.
Question 23 Report
Which of the following has the lowest internal resistance when new?
Answer Details
Among the given options, the Accumulator has the lowest internal resistance when new. Internal resistance is the resistance that a battery or cell provides to the flow of electric current within itself. Lower internal resistance means that the battery can supply more current to an external circuit without losing much of its own energy as heat. An Accumulator, also known as a rechargeable battery, is designed to be charged and discharged multiple times. It has a relatively low internal resistance when new, meaning it can provide a higher current than the other cells listed while wasting less energy internally as heat. A Leclanche cell and Daniell cell are primary cells, meaning they are designed to be used once and discarded. They have higher internal resistance compared to the accumulator, which limits their ability to supply high currents. A Torch battery, also known as a dry cell, is also a primary cell and has a higher internal resistance than the accumulator. It is commonly used in small electronic devices and has a longer shelf life than Leclanche and Daniell cells. In summary, an Accumulator has the lowest internal resistance when new, which makes it an ideal choice for applications requiring high current delivery such as electric vehicles, power tools, and renewable energy systems.
Question 24 Report
What is the resultant resistance of the circuit in the image shown?
Answer Details
Formulae resistance in parallel
= 1/R = 1/R1 +1/R2
1/R = 1/2 +1/2 = 1
Resistance are now in series
R = 1 + 3 + 4
= 8 ohms
Question 25 Report
The photo cell works on the principle of the
Answer Details
The photocell works on the principle of the emission of electrons by incident radiation. In simple terms, a photocell is a device that converts light energy into electrical energy. It does this by using a material (such as silicon) that releases electrons when it is exposed to light. These electrons can then be collected and used to produce a current, which can be used to power an electrical device. The more light that hits the photocell, the more electrons are released and the greater the electrical current.
Question 26 Report
One of the features of the fission process is that
Answer Details
The fission process refers to the splitting of an atomic nucleus into two or more smaller nuclei. One of the key features of the fission process is that it can lead to a chain reaction, where the neutrons released during fission can go on to trigger additional fission reactions. This chain reaction can produce a large amount of energy, as is the case in nuclear power plants and nuclear weapons. Another feature of the fission process is that it typically produces radioactive products. These products can remain radioactive for a long time, which is why there are concerns about the safe disposal of nuclear waste. Additionally, the fission process typically releases neutrons, which can go on to cause further fission reactions. This neutron release is an important aspect of the chain reaction mentioned earlier. Finally, the fission process is accompanied by a small loss of mass, which is converted into energy according to Einstein's famous equation E=mc². This loss of mass is what allows the large amount of energy to be released during a fission reaction.
Question 27 Report
An object is placed 20cm from a concave mirror of focal length 10cm. The linear magnification of the image produced is?
Answer Details
The linear magnification of an image is given by the formula: magnification = height of image / height of object = -v/u where v is the image distance, u is the object distance, and the negative sign indicates that the image is inverted. In this problem, the object is placed 20cm from a concave mirror of focal length 10cm. Since the object is placed beyond the focal point, the image will be real and inverted. Using the mirror formula 1/f = 1/v + 1/u, we can find the image distance v: 1/10 = 1/v + 1/20 Solving for v, we get: v = -20 cm Now, we can use the magnification formula to find the linear magnification: magnification = -v/u = -(-20)/20 = 1 Therefore, the linear magnification of the image produced is 1, which means the image is the same size as the object and is also inverted. The answer is: 1.
Question 28 Report
An object weighs 30N in air and 21N in water. The weight of the object when completely immersed in a liquid of relative density 1.4 is
Answer Details
Weight of water displaced = upthrust = 30 - 21 = 9N
Mass of water displaced = 910
= 0.9kg
Volume of object = 9 × 10−4
m3
= (9 × 10−4
) (1.4 ×103)
= 1.26kg = 12N
30 - 12.6 = 17.4N
Question 29 Report
Which of the following phenomena is the practical evidence for the existence of the continual motion of molecules.
Answer Details
Brownian motion is the practical evidence for the existence of the continual motion of molecules. This phenomenon is observed as the random movement of particles suspended in a fluid, such as a liquid or a gas, due to the constant bombardment of the fluid molecules. It was first described by the Scottish botanist Robert Brown in 1827 and provides strong evidence for the kinetic theory of matter, which states that all matter is made up of constantly moving particles. The random movement of the suspended particles can be observed through a microscope and is a direct result of the continual motion of the fluid molecules.
Question 30 Report
Which of the following does NOT describe the Image formed by a plane minor?
Answer Details
The option that does NOT describe the image formed by a plane mirror is "Magnified". When an object is placed in front of a plane mirror, the image formed is: 1. Erect: The orientation of the object in the mirror is the same as the orientation of the object in real life. For example, if you raise your right hand in front of a plane mirror, the image in the mirror will also show your right hand raised. 2. Laterally inverted: The image formed in the mirror is flipped horizontally, which means that the left side of the object appears on the right side of the image and vice versa. For example, if you wear a shirt with the letter "H" on it and look at it in a plane mirror, the image will show the letter "H" flipped horizontally. 3. Same distance from the mirror as object: The image formed in the mirror is located behind the mirror at the same distance as the object is located in front of the mirror. For example, if you stand 1 meter away from a plane mirror, the image of yourself will also be located 1 meter away from the mirror, behind the mirror. 4. NOT magnified: The image formed in the plane mirror is of the same size as the object, which means that there is no magnification or reduction in the size of the image. For example, if you stand in front of a plane mirror with a height of 1 meter, the image of yourself in the mirror will also have a height of 1 meter. Therefore, the correct answer is "Magnified", as the image formed by a plane mirror is not magnified.
Question 31 Report
Which of the following obeys Ohm's law?
Answer Details
Ohm's law states that the current passing through a conductor is directly proportional to the voltage applied across it, given the temperature and other physical conditions remain constant. Among the given options, only "all metals" obey Ohm's law. This is because metals have a linear relationship between their resistance and the applied voltage, meaning that the resistance of a metal remains constant regardless of the voltage applied. As a result, the current passing through a metal is directly proportional to the voltage applied, following Ohm's law. On the other hand, a diode, all electrolytes, and glass do not obey Ohm's law. A diode is a semiconductor that has a non-linear current-voltage relationship, and its resistance is not constant. Similarly, electrolytes and glass are non-metallic substances that do not have a linear relationship between their resistance and the applied voltage. Their resistance can change significantly with the voltage applied, and hence they do not follow Ohm's law.
Question 32 Report
An electric heating coil rated at 1KW is used to heat 2kg of water for 2 minutes. The initial water temperature is 30o C. Taking the specific heat of the water as 4,000Jkg −1 and neglecting that of the container, the final water temperature is
Answer Details
To determine the final temperature of the water, we can use the formula: Q = mcΔT where Q is the heat transferred, m is the mass of the water, c is the specific heat capacity of water, and ΔT is the change in temperature. We know that the power of the electric heating coil is 1KW, which means it transfers 1000 Joules of energy per second. In 2 minutes, or 120 seconds, it transfers 120,000 Joules of energy to the water. The mass of the water is given as 2kg and the specific heat capacity of water is 4000 J/kg°C. We can assume that the initial temperature of the water is 30°C. Using the formula, we can solve for the change in temperature: 120,000 J = (2 kg)(4000 J/kg°C)(ΔT) ΔT = 15°C Therefore, the final temperature of the water is 30°C + 15°C = 45°C. So, the final water temperature is 45.0oC.
Question 33 Report
Calculate the effective capacitance of the circuit in the diagram given
Answer Details
The three 2uf capacitors are in parallel to each other so u add them like this
2uf+2uf+2uf=6uf
So u have three capacitors in series
6uf 2uf and 3uf
They are in series so
1/C= 1/6+1/3=1/2
C=2uf
Then the same thing with the last two capay
1/2+1/2=1uf
Thanks
Question 34 Report
The time rate of loss of heat by a body is proportional to the
Answer Details
The correct answer is "difference in temperature between the body and its surroundings." When a body is at a higher temperature than its surroundings, it will lose heat to the surroundings until it reaches thermal equilibrium, i.e., until the temperatures of the body and its surroundings are equal. The rate at which the body loses heat is proportional to the temperature difference between the body and its surroundings. This is known as Newton's law of cooling. The law of cooling applies to a wide range of situations, from the cooling of hot beverages to the cooling of electronic devices. It is important to understand this law because it allows us to predict how long it will take for a body to cool down to a certain temperature, and to design systems that can regulate the temperature of a body, such as heaters or refrigerators.
Question 35 Report
Which of the following phenomena cannot be explained by the molecular theory of matter?
Answer Details
Conduction: the flow of internal energy from a region of higher temperature to lower temperature
Convection: heat transfer due to bulk movement of molecules within fluids
Expansion: the action of becoming larger or more extensive
Question 36 Report
An object moves in a circular path of radius 0.5m with a speed of 1ms−1 . What is its angular velocity?
Answer Details
Angular velocity is a measure of how fast an object is rotating around a center point. It's usually measured in radians per second (rad/s). To calculate angular velocity, we use the formula: angular velocity = linear velocity / radius. In this case, the linear velocity is 1 m/s, and the radius is 0.5 m. So, the angular velocity would be: 1 m/s / 0.5 m = 2 rad/s Therefore, the answer is 2 rad/s or 2rads^-1
Question 37 Report
Which of the following statements are TRUE of isotopes?
I. Isotopes of an element have the same chemical properties because they have the same number of electrons
II. Isotopes of elements are normally separated using physical properties
III. Isotopes of an element have the same number of protons in their nuclei
Answer Details
The correct answer is "I and III only". Isotopes of an element have the same number of protons in their nuclei, meaning they have the same atomic number and are therefore the same element. Because of this, they have the same chemical properties. However, isotopes of an element have different numbers of neutrons in their nuclei, which means they have different atomic masses. This is why isotopes can be separated using physical properties such as their mass or other characteristics related to their mass.
Question 38 Report
A particle of mass M initially at rest splits into two. If one of the particles of mass M1 moves with velocity V1 , the second particle moves with velocity
Answer Details
When a particle of mass M splits into two, the total mass is conserved, and so the sum of the masses of the two resulting particles must be equal to M. If one of the particles of mass M1 moves with velocity V1, we can use the law of conservation of momentum to determine the velocity of the second particle. The law of conservation of momentum states that the total momentum of a system of particles remains constant if no external forces act on the system. In this case, the initial momentum of the system is zero, since the particle was initially at rest. After the particle splits, the momentum of the system is the sum of the momenta of the two resulting particles. Let's use the subscript 1 to represent the first particle of mass M1 and the subscript 2 to represent the second particle of mass M-M1. By conservation of momentum, we have: 0 = M1*V1 + (M - M1)*V2 Solving for V2, we get: V2 = -M1/M*(V1) Therefore, the second particle moves in the opposite direction with velocity -M1/M*(V1). This means that the two particles move in opposite directions, with the ratio of their velocities determined by the ratio of their masses. Option (D) in the table shows the correct answer, which is -M1/M*(V1).
Question 39 Report
Which of the following is the dimension of pressure
Answer Details
The dimension of pressure is ML-1T-2 Pressure is defined as the force per unit area. This means that pressure is dependent on the force applied and the area over which it is applied. The unit of force is measured in Newtons (N), and the unit of area is measured in square meters (m2). Therefore, the unit of pressure is N/m2, which is also known as Pascals (Pa). To determine the dimension of pressure, we need to break down the units into their fundamental dimensions of mass (M), length (L), and time (T). Force is measured in N, which is kg m/s2. Area is measured in m2, which is L2. Therefore, the dimension of pressure can be calculated as (kg m/s2)/(L2), which simplifies to ML-1T-2.
Question 40 Report
The electrochemical equivalent of silver is 0.0012g/C. If 36.0g of silver is to be deposited by electrolysis on a surface by passing a steady current for 5mins, the current must be?
Answer Details
The electrochemical equivalent of silver is a measure of the amount of silver that is deposited on a surface per unit of charge. In this case, the electrochemical equivalent of silver is 0.0012 grams per Coulomb of charge. To deposit 36.0 grams of silver by electrolysis, we need to know the amount of charge that must be passed through the solution. The amount of charge is given by: Q = m/z where m is the mass of silver to be deposited, 0.0012 is the electrochemical equivalent of silver, and z is the charge on one mole of electrons (z = 1 for a single electron). So, the amount of charge required is: Q = 36.0 g / 0.0012 g/C = 30000 C The current, I, is given by: I = Q / t where t is the time for which the current is flowing. In this case, t = 5 minutes. So, the current required is: I = 30000 C / (5 x 60 s) = 100 A Therefore, the current must be 100 Amperes.
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