The following that describes an electric insulator are :
C. A material that has a high resistance and prevents charges from moving freely.
The following that describes an electric insulator is a material that has a high resistance and prevents charges from moving freely. The conductors exhibit low resistance, which allows for the flow of current through it freely.Thus, the correct answer is C.
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Answer:
42.64
Explanation:
2x=2
7x=5
12x=1.4
17.5x=21.5
A teacher gives students a sunglasses lens and asks them to observe the surface of a pond on a sunny day. The students notice that the water on the surface of the pond appears brighter and then dimmer when they rotate the lens as they look through it at the pond. The teacher asks the students to explain this observation. Which of the following student statements provides a correct explanation?
A. The lenses of the sunglasses absorb and transmit light of different wavelengths or offerent angles of lens rotation, thus transmitting more or less light to our eyes
B. Rotating the sunglasses changes the index of retraction of the lenses, co more light is tetracted away from our eyes at some angles
C. Only some of the light is reflected from the surface of the pond and rotating the lens causes more or less light to be transmitted at some angles
D. The light is linearly polarized when it is reflected off the surface of the pond, and the lens is a polariangles that transmits more light at certain angles
Answer:
Option D
Explanation:
Option (A) is incorrect because transmission of few wavelength will procure visibility of only few colours and not all. Option B is also incorrect as refraction index remains same as it does not changes with the change in angle. Option C is also incorrect because changing orientation of only some of the light with not make any significant difference
Option D is correct because sunlight is a unpolarised light which can be polarised using reflection. Now when sunlight gets partially linearly polarized after reflection from the lake, it can be viewed by the observer's eye through the lens.
B is the statements provide is a correct explanation. Rotating the sunglasses changes the index of refraction of the lenses, so more light is retracted away from our eyes at some angles.
What is a refractive index?The refractive index n is defined as the ratio of the sine of the incidence angle to the sine of the refraction angle, i.e., n = sin I / sin r.
The velocity of light c of a given wavelength in empty space divided by its velocity v in a substance, or n = c/v, is also equal to the refractive index.
Rotating the sunglasses changes the index of refraction of the lenses, so more light is retracted away from our eyes at some angles.
Hence option B is correct.
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Platinum is used in resistance thermometer for industrial applications because of?
platinum is used because it is more stable, provides accurate results and has a broad temperature range.
1
1 point
The table shows the lengths and diameters of four copper wires.
Which wire has the least resistance?
length/m
diameter/mm
A
0.50
1.0
B
0.50
2.5
С
0.75
1.0
D
0.75
2.5
А
B
D
Answer:
where is the table?????????
The wire has a length of 0.50 m and a diameter of 2.5 mm and has the least resistance, so, option B is correct.
What is resistance?A substance's ability to obstruct the flow of electrical current is referred to as resistance. It is symbolized by the capital letter R. The ohm, frequently written as a word and sometimes represented by the capital Greek letter omega, is the unit of resistance that is typically used.
Given:
The length of the wire A = 0.50 m and the diameter is 1 mm,
The length of the wire B = 0.50 m and the diameter is 2.5 mm,
The length of the wire C = 0.75 m and the diameter is 1 mm,
The length of the wire D = 0.75 m and the diameter is 2.5 mm,
Calculate the L / Area factor of all the wires as shown below,
L / Area factor of A = 0.50 / π × 0.0005²
L / Area factor of A = 636619.8
L / Area factor of B = 0.50 / π × 0.00125²
L / Area factor of B = 101859
L / Area factor of C = 0.75 / π × 0.0005²
L / Area factor of C = 955414
L / Area factor of D = 0.75 / π × 0.00125²
L / Area factor of D = 152866
As we can see, if the L / Area factor of B is less, then its resistance will be the least.
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A diver comes off a board with arms straight up and legs straight down, giving her a moment of inertia about her rotation axis of 18kg⋅m2. She then tucks into a small ball, decreasing this moment of inertia to 3.6kg⋅m2. While tucked, she makes two complete revolutions in 1.2s.
Required:
If she hadn't tucked at all, how many revolutions would she have made in the 1.5 s from board to water?
Answer:
θ₁ = 0.5 revolution
Explanation:
We will use the conservation of angular momentum as follows:
[tex]L_1=L_2\\I_1\omega_1=I_2\omega_2[/tex]
where,
I₁ = initial moment of inertia = 18 kg.m²
I₂ = Final moment of inertia = 3.6 kg.m²
ω₁ = initial angular velocity = ?
ω₂ = Final Angular velocity = [tex]\frac{\theta_2}{t_2} = \frac{2\ rev}{1.2\ s}[/tex] = 1.67 rev/s
Therefore,
[tex](18\ kg.m^2)\omega_1 = (3.6\ kg.m^2)(1.67\ rev/s)\\\\\omega_1 = \frac{(3.6\ kg.m^2)(1.67\ rev/s)}{(18\ kg.m^2)}\\\\\omega_1 = \frac{\theta_1}{t_1} = 0.333\ rev/s\\\\\theta_1 = (0.333\ rev/s)t_1[/tex]
where,
θ₁ = revolutions if she had not tucked at all = ?
t₁ = time = 1.5 s
Therefore,
[tex]\theta_1 = (0.333\ rev/s)(1.5\ s)\\[/tex]
θ₁ = 0.5 revolution
A bat emits a 40 kHz chirp to locate flying insects. If the speed of sound is 340 m/s and a bat hears the echo from the moth after 0.6 seconds, then how far away is the moth?
102 m
Explanation:
The time 0.6 sec is the time it took for the sound to travel from the bat to the moth and back. So it took 0.3 sec for the sound to reach the moth. From the definition of speed, the distance of the moth d to the bat is given by
v = d/t ---> d = vt = (340 m/s)(0.3 sec) = 102 m
Which diagram shows magnets that will attract each other? 2 bar magnets side by side with their long axes vertical, both red S on top and blue N on bottom. 2 bar magnets top to bottom with their long axes vertical, the top one with red S on top and blue N on bottom and the bottom magnet with blue N on top and red S on bottom. 2 bar magnets top to bottom with their long axes vertical, the top one with blue N on top and red S on bottom and the bottom magnet with red S on top and blue N on bottom. 2 bar magnets top to bottom with their long axes vertical, the top one with red S on top and blue N on bottom and the bottom magnet with red S on top and blue N on bottom.
2 bar magnets top to bottom with their long axes vertical, the top one with red S on top and blue N on bottom and the bottom magnet with red S on top and blue N on bottom. this diagram shows magnets that will attract each other. Hence option D is correct.
What is Magnet ?A permanent magnet is an item constructed of magnetised material that generates its own persistent magnetic field. A refrigerator magnet, for example, is commonly used to hold notes on a refrigerator door. Ferromagnetic (or ferrimagnetic) materials are those that can be magnetised and are strongly attracted to a magnet. These include the elements iron, nickel, and cobalt, as well as their alloys, some rare-earth metal alloys, and naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones that are strongly attracted to a magnet and are widely thought to be magnetic, all other substances respond weakly to a magnetic field via one of many different forms of magnetism.
Hence option D is correct.
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An echo is heard from a building 0.4 s after you shout "hello." How many feet away is
the building if the air temperature is 27°C? (Velocity of sound in air at 0°C is 1087 ft/s)
Answer:
Circular motion: find period, find radius, find velocity, find centripetal acceleration 27 V= T a =vºlr=rw
Explanation:
When an object is fully converted into energy the amount of energy liberated is
3.6×1017 J, what is the mass of the substance?
Answer:
Mass, m = 4 kg
Explanation:
Given the following data;
Energy = 3.6 * 10^17 Joules
We know that the speed of light is equal to 3 * 10⁸ m/s.
To find the mass of the substance;
The theory of special relativity by Albert Einstein gave birth to one of the most famous equation in science.
The equation illustrates, energy equals mass multiplied by the square of the speed of light.
Mathematically, the theory of special relativity is given by the formula;
[tex] E = mc^{2} [/tex]
Where;
E is the energy possessed by a substance.m is the mass.c is the speed of light.Substituting into the formula, we have;
[tex] 3.6 * 10^{17} = m * 300000000^{2} [/tex]
[tex] 3.6 * 10^{17} = m * 9*10^{16} [/tex]
[tex] m = \frac {3.6 * 10^{17}}{9*10^{16}} [/tex]
Mass, m = 4 kg
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otd-vbut-uao
Answer:
Weird
Explanation:
Tara kain tayo sardinas lang ulam
A cargo spacecraft was orbiting the earth. It is equipped with rocket and has an initial mass of 30 metric ton. It wants to catch up with the international space station to deliver the cargo. So its rocket engine was fired for 1 minute. The engine ejects mass at a rate of 30 kg/s with an exhaust velocity of 3.1 km/s. The pressure at the nozzle exit is 5 kPa and the diameter of exit area is 94.4 cm. What is the thrust of the engine in a vacuum
Answer:
Explanation:
A cargo spacecraft was orbiting the earth. It is equipped with rocket and has an initial mass of 30 metric ton. It wants to catch up with the international space station to deliver the cargo. So its rocket engine was fired for 1 minute. The engine ejects mass at a rate of 30 kg/s with an exhaust velocity of 3.1 km/s. The pressure at the nozzle exit is 5 kPa and the diameter of exit area is 94.4 cm. What is the thrust of the eng
Show that if you have three polarizing filters, with the second at an angle of 45 degrees to the first and the third at an angle of 90 degrees to the first, the intensity of light passed by the first will be reduced to 25% of its value. (This is in contrast to having only the first and third, which reduces the intensity to zero, so that placing the second between them increases the intensity of the transmitted light.)
Answer:
I₃ /I₀ = 25%
Explanation:
For this exercise let's use Malus's law
I = I₀ cos² θ
where tea is the angle between the two polarizers.
When the polarized light passes the first polarizer, the intensity is constant if it is in the direction of polarization.
I₁ = I₀
the light transmitted by the second polarizer is
I₂ = I₁ cos² θ
I₂ = I₀ cos² 45
I₂ = I₀ 0.5
this light is polarized 45º with respect to the first polarizer
Now let's examine the third polarizer, it is indicated that it has an angle of 90º with respect to the first polarizer, the angle with respect to the second polarizer is
θ = 90 - 45
θ = 45º
so the polarizer is at an angle of 45º
let's use Maus's law
I₃ = I₂ cos² 45
I₃ = I₀ 0.5 cos² 45
I₃ = I₀ 0.25
the light that passes through the system is
I₃ /I₀ = 0.25
as a percentage we multiply by 100
I₃ /I₀ = 25%
Please please help me please please help please please
Answer:
Refraction
The rainbow is created because the index of refraction of water droplets changes as a function of wavelength. So, when the light enters the water droplet different colors will bend at different angles thus producing a dispersive effect known as a rainbow.
Answer:
D: Refraction
Explanation:
Refraction is the spitting of the electromagnetic spectrum, or the disembling of colours. For example, white is a mixture of all the colours.
1. Light moving through air is incident on a piece of crown glass (1.61) Jt an angle of 45. What is the angle of refraction?
The shape of the orbit for most comets is a(n):
circle
parabola
ellipse
oval
Answer:
Ellipse
Explanation:
Most comets have an elliptical path of orbit.
Answer: The shape of the orbit for most comets is: ellipse
You are exploring a small moon of a distant planet. Measurements indicate that this moon is a sphere of uniform density rho = 5000 kg/m3. You dig a very deep hole into the moon that reaches within r0 = 1000 m of the center of the moon. With your spacesuit, you have a mass of m = 85 kg. Find the force of gravity on you when you stand at the bottom of the hole.
Answer:
The force of gravity will be "0.11874 N"
Explanation:
The given values are:
Density of planet,
Q = 5000 Kg/m³
Inside radius,
r₀ = 1000 m
Now,
The mass of inside sphere will be:
⇒ [tex]m_p=density\times volume[/tex]
⇒ [tex]=5000\times \frac{4}{3}\pi r^3[/tex]
On putting the values, we get
⇒ [tex]=5000\times \frac{4}{3}\times \pi\times (1000)^3[/tex]
⇒ [tex]=85 \ kg[/tex]
hence,
The force of gravity will be:
= [tex]\frac{Gm_{planet} m_{person}}{r^2}[/tex]
= [tex]\frac{6.67\times 10^{-11}\times 5000\times 4\pi\times 85\times 1000}{3}[/tex]
= [tex]\frac{6.67\times 10^{-11}\times 4\pi\times 425000000}{3}[/tex]
= [tex]0.11874 \ N[/tex]
A polar bear walks 2.5 meters to the right and then back to the left to exactly where he started. His displacement would be
?
A.
5 meters
B.
2.5 meters
C.
O meters
D.
No way to determine with given information
The figure below shows regions of the electromagnetic
spectrum
Gamma
Radio Microwaves Infrared Visible Ultraviolet X-rays Rays
Which of the following waves has the highest frequency?
{GAMMA RAYS}
Answer:
The electromagnetic spectrum in order of increasing frequency is - radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
The frequency of the gamma rays is >3×10
19
m.
Hence, the gamma rays has the maximum frequency in the electromagnetic spectrum.
What is the direction of the magnetic force on a positive charge that moves as shown in each of the six cases shown?
Answer:
D:because magmetic force are like factor but the angles of MAGNETIC and FACTORS are same as well!!it soposed to be like force and 1 by 1 to be divided and multiply thus...the DECIMAL have nothing to involved!!
Explanation:
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Answer:
A major challenge in the drug delivery field is to enhance transport of therapeutics across biological barriers such as the blood brain barrier (BBB), the small intestine, nasal, skin and the mouth mucosa.
Answer:
An aqueous stagnant layer that overlies the apical membrane and the subepithelial blood flow are potential barriers to the absorption of drugs that readily penetrate the absorbing cell of the epithelium. The apical, basal, and basement membranes are potential barriers to the absorption of less permeable drugs
A cup has a mass of 0.0650 kg and a
volume of 0.000250 m3, and is floating in fresh water. Pennies are put into the
cup until the top of the cup is level with the water line. What is the mass of the
pennies in the cup?
Answer: 0.185
Explanation:
Trust bro
The correct answer about law of floatation is, “0.185 kg”.
What are the conditions for object to float on water?The object's average density must be lower than the density of the fluid in which it must float.The fluid's upward push force on the item must match the object's entire weight.The objects's volume which is submerged in water has to be large enough so that a large amount of water can be displaced.
What is law of floatation?
When a body which is floating in a liquid, the amount of weight of liquid that is displaced by the body's submerged portion equals the body's total weight.
How to solve this question?
Volume of water that the cup has displaced = volume of cup
Volume of water that the cup has displaced = 0.000250 m³
Mass of water the cup has displaced = Density of water × Volume of water that the cup has displaced
Given that 1000 kg/m³ is the water density,
Mass of water the cup has displaced = 1000 X 0.000250 = 0.250 kg
Mass of water the cup has displaced = 0.250 kg
By law of flotation
Mass of water the cup has displaced = Mass of cup + Mass of pennies
0.250 Kg = 0.065 Kg + Mass of pennies in the cup (in Kg)
Mass of pennies in the cup = 0.250 - 0.065
Mass of pennies in the cup = 0.185 kg
Hence the mass of the pennies in cup came out be 0.185 Kg after solving.
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A record is spinning on a turntable. A record is a uniform disk of mass 1.00 kg and a radius of 0.13 m that spins around an axis through its center. The record is initially spinning at 10 rad/s. Then the motor is turned off and the record slows to a stop with constant angular acceleration. As the record is slowing down it spins through 6.37 revolutions. What is the magnitude of the net torque acting on the record as it slows down
Answer:
T = 0.01 Nm
Explanation:
First, we will calculate the angular acceleration of the disk:
[tex]2\theta\alpha = \omega_f^2-\omega_i^2[/tex]
where,
θ = angular displacement = (6.37 rev)(2π rad/1 rev) = 40.02 rad/s
α = angular acceleration = ?
ωi = initial angular speed = 10 rad/s
ωf = final angular speed = 0 rad/s
Therefore,
[tex](2)(40.02\ rad/s)\alpha = (0\ rad/s)^2-(10\ rad/s)^2[/tex]
α = -1.25 rad/s²
negative sign shows deceleration
α = 1.25 rad/s²
Now, we will calculate the moment of inertia of disk:
[tex]I = \frac{1}{2}mr^2[/tex]
where,
I = Moment of Inertia = ?
m = mass of disk = 1 kg
r = radius of disk = 0.13 m
Therefore,
[tex]I = \frac{1}{2} (1\ kg)(0.13\ m)^2[/tex]
I = 0.00845 kg.m²
Now, the torque can be given as:
T = Iα
T = (0.00845 kg.m²)(1.25 rad/s²)
T = 0.01 Nm
Convert 125 mL to L
Answer:
1 L = 1000 mL
125 mL = 125/1000 = 0.125 L
Answer:
0.125
Explanation:
divide by 1 000 to convert mL to liters
How does competition affect population size? Use the terms carrying capacity and limiting factor with your example.
Limiting factors are resources or other factors in the environment that can lower the population growth rate. Competition for resources like food and space cause the growth rate to stop increasing, so the population levels off. This flat upper line on a growth curve is the carrying capacity.
Answer:
they can eat all of the food and kill off the population
Explanation:
if the competition eats all of the food there's no food for the population and they will die off.
Please help, confused on this whole lesson
Answer:
1,4,3and 2 would happen hope this helps
Two organisms that can reproduce and produce fertile offspring are defined as a: *
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Prompt: How does melanin provide protection against skin cancer?
Read and annotate the second paragraph of the "What Is Melanin?" article, then write an
explanation of how this evidence helps answer the question. Use the following words in your
explanation: absorb, energy, light.
Answer:
Melanin is a protective pigment in skin, blocking UV radiation from damaging DNA and potentially causing skin cancer. Melanin does protect us, but this research shows it can also do us harm.
Definition:
UVA radiation causes lesions or DNA damage to melanocytes, which are the skin cells that produce the skin pigment known as melanin.
Explanation:
Melanin is a pigment that is produced by cells known as melanocytes in the skin of most animals, including humans. This pigment comes in different shades, depending on the genetic makeup of the individual. Melanin comes in two basic forms and can range from yellowish-red to dark brown. Eumelanin is the most common form of melanin and is brownish in color. The other basic form is called pheomelanin, which produces reddish-brown color that is often associated with freckles and red hair. The production of melanin in the individual is determined by several factors.
Genetically speaking, every individual on Earth has approximately the same number of melanocytes. The difference, then, in the production of melanin is affected by:
Exposure to UV radiation: Melanin is produced as a response to UV radiation in order to prevent damage to the DNA in the integument. Individuals, who are exposed to UV light, such as the sun, will produce more melanin for protection.
Genetic makeup: Different ethnicities and cultures are genetically pre-disposed to producing particular shades and amounts of melanin due to inheritance. This is, essentially, one of the primary indicators used in determining race in the human population. It is important to note that this is, and has historically been, a controversial form of human identification.
Size of melanocytes: Melanocyte size varies in different individuals and may lead to a difference in the amount of melanin produced per cell.
Disease conditions: Several diseases may affect melanin production, including albinism, a genetic inability to produce melanin, and vitiligo, a progressive loss of melanocytes.
A 10 kg medicine ball is thrown at a velocity of 15 km/hr ( m/s) to a 50 kg skater who is
at rest on the ice. The skater catches the ball and subsequently slides with the ball across the
ice.
Complete Question
A 10 kg medicine ball is thrown at a velocity of 15 km/hr ( m/s) to a 50 kg skater who is at rest on the ice. The skater catches the ball and subsequently slides with the ball across the ice.
Calculate the kinetic energy after collision(in joules).
Answer:
[tex]K.E=70.23J[/tex]
Explanation:
From the question we are told that:
Mass of ball [tex]m_b=10kg[/tex]
Speed [tex]V_{b1}=15 km/hr ( m/s)[/tex]
[tex]V_{b1} = 4.1667 m/s[/tex]
[tex]V_{b1} = 4.1667 m/s[/tex]
Mass of Skater [tex]m_s=50kg[/tex]
Generally the equation for conservation of momentum is mathematically given by
[tex]m_sV_{s1}+m_bV_{b1}=(m_s+m_b)V[/tex]
[tex]V=\frac{m_sV_{s1}+m_bV_{b1}}{(m_s+m_b)}[/tex]
[tex]V=\frac {50+10*4.1667}{(50+10)}[/tex]
[tex]V=1.53m/s[/tex]
Generally the equation for Kinetic energy is mathematically given by
[tex]K.E=\frac{1}{2}(m_s+m_b)V^2[/tex]
[tex]K.E=\frac{1}{2}(50+10)(1.53)^2[/tex]
[tex]K.E=70.23J[/tex]
Therefore kinetic energy K.E after collision is given as
[tex]K.E=70.23J[/tex]
what do electrons and holes make when they are moving
Answer:
Holes are formed when electrons in atoms move out of the valence band (the outermost shell of the atom that is completely filled with electrons) into the conduction band. (the area in an atom where electrons can escape easily) which happens everywhere in a semiconductor. When an electron and a hole interact and recombine the energy is not transferred into heat energy or thermal vibrations. instead the energy is transferred into an electron within the conduction band which is then promoted to an energy higher in condition band.
Explanation:
So considering that information, electrons and holes make a semiconductor when moving.
If mass is a measure of inertia of a body at rest, then momentum is a measure of inertia of a body _____
Answer:
Momentum is a measure of inertia in motion. Momentum is equal to mass multiplied by velocity. A 2250 kg pickup has a velocity of 25 m/s east.
Explanation:
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