Answer:
Option D (Electricity can flow through it under special conditions ) seems to be the correct choice.
Explanation:
A semiconductor has become a crystal substance with improved electrochemical properties although the temperature is increased. That would be to say, it often functions as an insulating material rather than as a conductor or a circuit. Chemical solvents could perhaps greatly enhance its conducting capacity.Other options that are provided are not related to the given theory. So that the above would be the correct choice.
Statement "Lack free electrons that can move to other atoms " describe semi-conductor.
Properties of Semiconductor:A semiconductor is a type of crystalline solid that is halfway between a conductor and an insulator in terms of electrical conductivity. A semiconductor is conducting in nature because it has free electrons and holes.So that, Lack free electrons that can move to other atoms.Learn more about the Semiconductor here:
https://brainly.com/question/1918629
An average skater averages 11 m/s over the first 5 seconds of a race. find the average speed required over next 10 seconds to average 12 m/s overall.
Answer:
usa
Explanation:
Question 2 of 10
Which of the following is an Sl unit?
A. Foot
B. Inch
C. Meter
D. Mile
SUBMIT
Answer:
C. Meter
Explanation:
The International System of Unit (SI) is gotten from the french word Systeme international is a modern form of metric measurement. It is the system of measurement that is universally accepted. It is from this SI units that all other system of units are derived. There are seven basic SI units which are:
1) Length in Meter (m)
2) Time in Seconds (s)
3) Amount of Substance in mole (m)
4) Electric current in ampere (A)
5) Temperature in kelvin (k)
6) Luminous intensity in candela (cd)
7) Mass in kilogram (kg)
The rhinestones in costume jewelry are glass with index of refraction 1.50. To make them more reflective, they are often coated with a layer of silicon monoxide of index of refraction 2.00. What is the minimum coating thickness needed to ensure that light of wavelength 480 nm and of perpendicular incidence will be reflected from the two surfaces of the coating with fully constructive interference?
Answer:
60
Explanation:
According to the given question, the computation of minimum coating thickness is shown below:-
The condition for constructive interference is
[tex]2t_{min} = (m + \frac{1}{2} )\times \frac{\lambda}{^nmateral}[/tex]
[tex]= (0 + \frac{1}{2} )\times \frac{\lambda}{^nmateral}[/tex]
[tex]t = \frac{\lambda}{4n}[/tex]
Now we will put the values to the above formula to reach the answer
[tex]= \frac{480nm}{4\times 2.0}[/tex]
= 60
Therefore we simply applied the above formula to determine the minimum coating thickness
The minimum coating thickness needed to ensure that light of wavelength 480 nm and of perpendicular incidence will be reflected from the two surfaces of the coating with fully constructive interference is 60.
Given that, the index of refraction of glass is 1.50 and the index of refraction of silicon monoxide is 2.00. The wavelength light of 480 nm.
If [tex]\lambda {c}[/tex] is the wavelength in the coating and λ is the wavelength in vacuum, then [tex]\lambda_{c} = \dfrac {\lambda}{n}[/tex] where n is the index of refraction of the coating.
Thus, the minimum coating thickness [tex]T_{min}[/tex] can be calculated as,
[tex]2T_{min} = (m+\dfrac {1}{2})\times\dfrac {\lambda} {n}\\\\T_{min} = (m+\dfrac {1}{2}) \times\dfrac {\lambda} {2n}[/tex].
For the constructive interference, m = 0.
So [tex]T_{min} = \dfrac {\lambda} {4n}[/tex]
[tex]T_{min} = \dfrac {480\rm nm} {4\times2.0}[/tex]
[tex]T_{min} = 60[/tex]
The minimum coating thickness needed to ensure that light of wavelength 480 nm and of perpendicular incidence will be reflected from the two surfaces of the coating with fully constructive interference is 60.
For more details, follow the link given below.
https://brainly.com/question/15541641.
Hi please may someone help me especially on the sketch part.
An object falls from a hovering helicopter and hits the ground at a speed of 30 m/s. How long does it take the object to reach the ground and how far does it fall? Sketch a velocity-time graph for the object (ignore air resistance).
Ignoring the air resistance it will take about 3 seconds for the object to reach the ground.We know that the acceleration due to gravity is 10m/s2.
We also know that the final velocity is 30 m/s while the initial velocity is 0 m/s
we can use the formulae for acceleration to calculate the time taken/
(final - initial velocity)/timetaken=10
(30-0)/timetaken=10
timetaken =30/10=3 seconds
an object is +2 m from the reference point. the object starts from rest it travels for 3 seconds and has a final position of -16 m. what is the acceleration of the object?
Answer:
Solution
Given:
initial velocity (u)=0m/s (because an object
starts from the rest)
time (t)=3sec
diatance travelled(s)=14m(16-2=14)
acceleration (a)=?
Now,
According to the formula
s=ut+1/2at^2
or,14 =0×3+1/2×a×3^2
or, 14=0+a/2×9
or, 14=9a/2
or, 9a=28
or, a=28/9
or, a=3.1 m/s^2
Therefore, the acceleration of the object is 3.1m/s^2 ans.
WILLL GIVE 5 STARS BRAINIEST AND THANKS AND 20 POINTS EACH ANSWER!!!!
A diver performs a dive from a 10 m-platform. She
jumps vertically upwards at 3 m s initially.
Find the time she takes to reach the water surface
Answer:
The time she takes to reach the water from when she jumps off the platform is 1.71 s
Explanation:
According to the equations of motion, we have;
v = u - g·t
v² = u² - 2·g·s
s₁ = u₁·t₁ + 1/2·g₁·t₁²
The given parameters are;
The height of the platform (assumption: above the water) = 10 m
The velocity with which she jumps, u = 3 m/s
The acceleration due to gravity, g = 9.81 m/s²
The height to which she jumps, s, is found as follows;
v² = u² - 2·g·s
At maximum height, v = 0, which gives;
0 = 3² - 2×9.81×s
2×9.81×s = 3² = 9
s = 9/(2×9.81) = 0.4587 m
s = 0.4587 m
The time to maximum height, t, is found as follows;
v = u - g·t
0 = 3 - 9.81×t
9.81×t = 3
t = 3/9.81 = 0.3058 s
The total distance, s₁ from maximum height to the water surface = s + 10 = 0.4587 + 10 = 10.4587 m = 10.46 m
The time to reach the water from maximum height, t₁, is found as follows;
s₁ = u₁·t₁ + 1/2·g₁·t₁²
Where;
s₁ = The total distance from maximum height to the water surface = 10.46 m
u₁ = The initial velocity, this time from the maximum height = 0 m/s
g₁ = The acceleration due to gravity, g (positive this time as the diver is accelerating down) = 9.81 m/s²
t₁ = The time to reach the water from maximum height
Substituting the values gives;
s₁ = u₁·t₁ + 1/2·g₁·t₁²
10.46 = 0·t₁ + 1/2·9.81·t₁²
t₁²= 10.46/(1/2×9.81) = 2.13 s²
t₁ = √2.13 = 1.46 s
Total time = t₁ + t = 1.46 + 0.3058 = 1.7066 ≈ 1.71 s.
Therefore, the time she takes to reach the water from when she jumps off the platform = 1.71 s.
A machine can never be 100% efficient because some work is always lost due to which factor? friction gravity static input force
Explanation:
Hi,
The answer is friction.
There is almost no machine which are not affected by friction. It losts some work due to friction while working.
Hope it helps..
Answer:
friction
Explanation:
the other options dont effect efficiency
A ball with a mass of 0.5 kg is attached to one end of a light rod that is 0.5 m long. The other end of the rod is loosely pinned at a frictionless pivot. The rod is raised until it is vertical, with the ball above the pivot. The rod is released and the ball moves in a vertical circle. The tension in the rod as the ball moves through the bottom of the circle is closest to:
Answer:
The tension in the rod as the ball moves through the bottom circle is 9.8 N
Explanation:
When the ball is released from rest, the centripetal force equals the weight of the ball. So mv²/r = mg where m = mass of ball = 0.5 kg, v = speed of ball, r = radius of vertical circle = length of rod = 0.5 m and g = acceleration due to gravity = 9.8 m/s²
v = √gr = √9.8 m/s² × 0.5 m = √4.9 = 2.21 m/s
Now at the bottom of the circle T - mg = mv²/r where T = tension in the rod
T = m(g + v²/r)
= m(g + (√gr)²/r)
= m(g+ gr/r)
= m(g + g)
= 2mg
= 2 × 0.5 kg × 9.8 m/s²
= 9.8 N
So, the tension in the rod as the ball moves through the bottom circle is 9.8 N
Based on its location on the periodic table, which element would be most likely to form a negative ion? A. Bromine (Br) B. Strontium (Sr) C. Potassium (K) D. Magnesium (Mg)
your answer is...
C. potassium
A train is moving along a horizontal track. A pendulum suspended from the roof makes an angle of 4° with the vertical. If g=10m/s2, what is the acceleration of the train?
Answer:
Train accaleration = 0.70 m/s^2
Explanation:
We have a pendulum (presumably simple in nature) in an accelerating train. As the train accelerates, the pendulum is going move in the opposite direction due to inertia. The force which causes this movement has the same accaleration as that of the train. This is the basis for the problem.
Start by setting up a free body diagram of all the forces in play: The gravitational force on the pendulum (mg), the force caused by the pendulum's inertial resistance to the train(F_i), and the resulting force of tension caused by the other two forces (F_r).
Next, set up your sum of forces equations/relationships. Note that the sum of vertical forces (y-direction) balance out and equal 0. While the horizontal forces add up to the total mass of the pendulum times it's accaleration; which, again, equals the train's accaleration.
After doing this, I would isolate the resulting force in the sum of vertical forces, substitute it into the horizontal force equation, and solve for the acceleration. The problem should reduce to show that the acceleration is proportional to the gravity times the tangent of the angle it makes.
I've attached my work, comment with any questions.
Side note: If you take this end result and solve for the angle, you'll see that no matter how fast the train accelerates, the pendulum will never reach a full 90°!
Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She wants to increase her time what should she do
Answer:
C. Walk four times per week
Explanation:
If she wants to increase her time then, she has to walk four times per week.
What is speed?The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is a meter/second. The generally considered unit for speed is a meter per second.
The mathematical expression for speed is given by
speed = total distance /Total time
As given in the problem Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She must walk four times a week if she wants to extend her time.
Thus, the correct answer is option C.
Learn more about speed from here, refer to the link;
brainly.com/question/7359669
#SPJ2
The question is incomplete, the complete question is,
Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She wants to increase her time. What should she do?
A. Walk at 4.5 miles per hour.
B. Walk for 50 minutes.
C. Walk four times per week.
D. Walk up and down more hills.
White light is spread out into its spectral components by a diffraction grating. If the grating has 1,970 grooves per centimeter, at what angle (in degrees) does red light of wavelength 640 nm appear in first order? (Assume that the light is incident normally on the gratings.)
Answer;
7.238°
Explanation
From question we know that the grating has 1,970 grooves per centimeter, we can convert to from (cm) to (nm) for unit consistency
The slit separation is expressed below
d=1cm/1970
d=0.0005076
=5076nm
Then the angle (in degrees) that the red light of wavelength 640 nm appear in first order can be calculated using expression below
Sin(x)= mλ/d
Where λ= wavelength=640 nm
d=slit separation
Sin(x)= mλ/d
Sin(x)=(1×640)/5076
=0.126
sin-1(0.126)
X= 7.238°
Therefore,the angle (in degrees) that the red light of wavelength 640 nm appear in first order is 7.238°
Select the correct answer. Rita is a registered dietician. What does her work entail? A. prescribing medication for clients B. cooking healthy meals for students C. demonstrating how to use gym equipment D. making recommendations for healthy eating habits
Answer:
D
Explanation:
The answer is D because:
A) Only doctors are allowed to prescribe medications.
B) Rita is not a chef/cook.
C) Rita is not a personal trainer
D) The job of a dietican is to provide reccomendations to their clients in order for them to implement a healthy lifestyle via consuming what is best for them.
Hope this helps :)
Answer:
D.) Making recommendations for healthy eating habits
Explanation: PLATO :)))
The ways to measure the mass and volume of irregular object
Answer:
When we have irregular objects, it may become very hard to calculate the volume of the object, as we actually can not use any simple equation to find it.
The mass is less tricky, just find a scale and wheight it, now we know the mass of the irregular object.
One way to measure the volume of the object is using water... how we do it?
Get some recipient with water, measure the height of the water.
Introduce your object into the water and totally submerge it, now the level of the water will rise. This is because as you introduce the object under the water, you are displacing up a given volume of water that has the same volume as the irregular object.
Now that you know the height of the water before and after you put your object, you can easily calculate the volume of water displaced, and that will be the volume of the object (the tricky part may be totally submerging the object if, for example, is wood and it floats, here you can use a thin wire to push it down but it will affect a little bit the measures.)
Calculate the average kinetic energy of molecules of a gas at a temperature of 18 ° C
Answer:
6.0×10⁻²¹ J
Explanation:
KE = 3/2 kT,
where KE is average kinetic energy per molecule,
k is the Boltzmann constant,
and T is absolute temperature.
KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K
KE = 6.0×10⁻²¹ J
Answer:
The answer is 6.0×10⁻²¹ J , because KE = 3/2 kT, where KE is average kinetic energy per molecule, k is the Boltzmann constant, and T is the absolute temperature.
KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K
KE = 6.0×10⁻²¹ J
What is the atomic number of hydrogen? A. 26 B. 14 C.35 D. 1
Answer:
1
Explanation:
Hydrogen is the first element in the periodic table so its atomic number is 1.
Which statement describes one feature of Rutherford's model of the atom?
O The atom is mostly empty space.
O The atom cannot be divided into smaller particles.
O Electron clouds are regions where electrons are likely to be found.
O The electrons are located within the positive material of the nucleus.
Answer:
The atom is mostly empty space.
Explanation:
Ernest Rutherford in the year 1911 developed a model of an atom. In his model the atom was shown that the atom is mostly empty spaces composed of negative electrons which orbits round a positive nucleus just like planets revolving round the sun.
Rutherford came up with this model by performing experiments in 1909 which involves the scattering of alpha particles on a thin gold foil. From this experiments he came up with his model.
Answer:
A!
Explanation:
The atom is mostly empty space.
A central air-conditioner uses 3500W of electricity. If electricity costs $0.087/kW*h. calculate how much it would cost to operate the air-conditioner 24 hours a day for 4 months (120 days).
Answer:
$876.96
Explanation:
The energy used is:
3500 W × (24 hr/day) × (120 day) × (1 kW / 1000 W) = 10,080 kWh.
So the cost is:
10,080 kWh × ($0.087 / kWh) = $876.96
The radius of a small ball is around 3.79747 cm. The radius of a basketball is about 3.16 times larger. What is the ratio of the surface areas of the small ball and a basketball? 2. What is the ratio of their volumes?
Explanation:
The ratio of the areas is the square of the ratio of the radii.
A/A = 3.16² = 9.99
The ratio of the volumes is the cube of the ratio of the radii.
V/V = 3.16³ = 31.6
An object accelerates to a velocity of 230 m/s over a time of 2.5 s. The acceleration it experienced was 42 m/s2. What was its initial velocity?
Answer:
230 = x + 105
x= 125
Explanation:
v = v0 + at
If you have a 200g sample of a radioactive isotope that has a half life of 50 years, hc
much will you have left at the end of 200 years?
a. 12.5 g
b. 100 g
c. 50 g
d. 25 g
Answer:
The correct option is;
a. 12.5 g
Explanation:
The given parameters are;
The initial mass of the radioactive substance = 200 g
The half life of the radioactive substance = 50 years
The time duration for the disintegration = 200 years
The formula for half life is given as follows;
[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}}[/tex]
Where:
N(t) = Quantity of the remaining substance
N₀ = Initial radioactive substance quantity = 200 g
t = Time duration = 200 years
[tex]t_{1/2}[/tex] = Half life of the radioactive substance 50 years
Therefore, we have;
[tex]N(t) =200 \times \left (\dfrac{1}{2} \right )^{\dfrac{200}{50} } =200 \times \left (\dfrac{1}{2} \right )^4 = 12.5 \ g[/tex]
Therefore, at the end of 200 years, the quantity left = 12.5 g.
Which two possible explanations does the video give for why white light changes into colored light? Color is an impurity added to white light by the prism. Color is present in the materials on which white light shines. White light contains seven colors, which are separated by the prism. White light reacts with chemicals in the air to produce seven colors.
Answer:
White light contains seven colors, which are separated by the prism.
White light reacts with chemicals in the air to produce seven colors.
Explanation:
It was first observed by Sir Issac Newton, that when white light is passed through a prism, an elongated, coloured patch of light is obtained on a screen placed behind the prism. The seven colours obtained constitute the spectrum of white light.
In nature, white light is separated into its constituent wavelengths when white light interacts with substances in the atmosphere.
Answer:
The correct answer is “color is an impurity added to white light by the prism.”
and
“White light contains seven colors, which are separated by the prism
Explanation:
Determine whether each sum, difference, product,
or quotient represents a rational number or an
irrational number. Explain how you know without
simplifying
Explanation:
The asked in the Question is missing, although i am assuming the number
as [tex]\frac{6}{23}[/tex] ÷[tex]\frac{\sqrt{2} }{2}[/tex].
The given expression contains an irrational number. So, the quotient will also be an irrational number.
Solving
[tex]\frac{6}{23}\times\frac{\sqrt{2} }{2} \\=\frac{3\sqrt{2} }{23}[/tex]
Which is an irrational number.
Determine the magnitude of the force that must be applied to a wooden block whose weight has a magnitude of 8N, so that it acquires an acceleration of 0.5 m / s²
Answer:
F = 0.408 N
Explanation:
It is given that,
Weight of a wooden block, W = 8 N
Weight, W = mg
m is mass of wooden block
[tex]m=\dfrac{W}{g}\\\\m=\dfrac{8\ N}{9.8\ m/s^2}\\\\m=0.816\ kg[/tex]
Acceleration of the block, a = 0.5 m/s²
Force, F = ma
[tex]F=0.816\ kg\times 0.5\ m/s^2\\\\F=0.408\ N[/tex]
So, the magnitude of force applied to the wooden block is 0.408 N.
Two mass m1 and m2 lie on a frictionless surface. Between the two masses is a compressed spring, with spring constant k. The system is held in place. At time t=0 the blocks are released. The blocks move off in opposite directions with velocities v1 and v2. how much was the spring compressed?
Answer:
The spring was compressed the following amount:
[tex]\Delta x=\sqrt{ \frac{m_1\,v_1^2+ m_2\,v_2^2}{k} }[/tex]
Explanation:
Use conservation of energy between initial and final state, considering that the surface id frictionless, and there is no loss in thermal energy due to friction. the total initial energy is the potential energy of the compressed spring (by an amount [tex]\Delta x[/tex]), and the total final energy is the addition of the kinetic energies of both masses:
[tex]E_i=\frac{1}{2} k\,(\Delta x)^2\\\\E_f=\frac{1}{2} m_1\,v_1^2+\frac{1}{2} m_2\,v_2^2[/tex]
[tex]E_i=E_f\\[/tex]
[tex]\frac{1}{2} k\,(\Delta x)^2=\frac{1}{2} m_1\,v_1^2+\frac{1}{2} m_2\,v_2^2\\k\,(\Delta x)^2=m_1\,v_1^2+ m_2\,v_2^2\\(\Delta x)^2=\frac{m_1\,v_1^2+ m_2\,v_2^2}{k} \\\Delta x=\sqrt{ \frac{m_1\,v_1^2+ m_2\,v_2^2}{k} }[/tex]
within a conventional light bulb, which of the following would not be considered a state of matter
a. the glass shell of the bulb
b. the metal base of the bulb
c. the air inside the bulb
d. the light from the bulb
Answer:
D
Explanation:
because light has no space nor mass
answer answer answer it it it
Answer:
Parachutes
Explanation:
Your parachute allows you to descend more slowly because it lowers terminal velocity by increasing your air resistance. Most parachutes are designed to create a large amount of drag and allow you to land at a safe, low speed.
HOPE THIS HELPS!!!
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A gauge is reading the pressure at the bottom of a river, at a depth of 6 m. Would the reading be greater or smaller than the reading at the bottom of a lake at the same depth? You must provide a clear explanation for full credit.
Answer:
The pressure at the bottom of the river is less than that at the bottom of the lake.
Explanation:
From Bernoulli's equation, the pressure difference is given by
ΔP = ρgΔh + ρ(v₂² - v₁²)/2 where ρ = density of water, g = acceleration due to gravity, Δh = depth, v₁ = velocity at top, v₂ = velocity at bottom
For the lake, v₁ = v₂, since the velocity at the top and bottom are the same. So,
ΔP₁ = ρgΔh + ρ(v₁² - v₁²)/2 = ρgΔh + 0 = ρgΔh
P₂ - P₁ = ρgΔh
P₂ = P₁ + ρgΔh
For the river, v₁ < v₂, since the velocity at the top of the river is greater than at the bottom.
So,
ΔP₂ = ρgΔh + ρ(v₂² - v₁²)/2.
Since v₁ < v₂, ρ(v₂² - v₁²)/2 will be negative,
So,
ΔP₂ = ρgΔh - ρ(v₂² - v₁²)/2.
Since ρ(v₂² - v₁²)/2 is negative, making ΔP less than that in the lake.
So, ΔP₂ = ΔP₁ - ρ(v₂² - v₁²)/2.
ΔP₂ = P₃ - P₁
P₃ - P₁ = P₂ - P₁ - ρ(v₂² - v₁²)/2.
P₃ = P₂ - ρ(v₂² - v₁²)/2.
where P₃ = pressure at bottom of the river and P₂ = pressure at bottom of the lake and P₁ = atmospheric pressure at top of river and lake respectively.
Since the factor ρ(v₂² - v₁²)/2 is removed from the pressure at the bottom of the lake, the pressure at the bottom of the river is therefore less than that at the bottom of the lake.
3) An earth moving machine uses diesel oil, which when burnt will produce 3.0x10 9 J of energy. The work performed by the machine is 2.7x 10 8 J. What is the efficiency of the machine?
Answer:
The answer is below
Explanation:
The efficiency of a machine is the ratio of its output to its input. The efficiency shows how effective the machine by the way it converts the input energy into work. The higher the efficiency of the machine the more effective it is. The efficiency is usually less than 1.
Given that the machine uses diesel oil (input) that can produce 3.0 x 10⁹ J of energy while the work performed by the machine (output) is 2.7 x 10⁸ J. The efficiency is given as:
Efficiency = output / input = 2.7 x 10⁸ J / 3.0 x 10⁹ J = 0.09 = 9%
This means that the machine is not effective because of its low efficiency
(02.10 LC)
Which American sport stems from a combination of the British sports rugby and soccer?
Baseball
Basketball
Tennis
Football
Question 2 Multiple Choice Worth 5 points)
Answer:
football
Explanation:
I took the 2.10 quiz and got it wrong so it must be football
