Answer:
The energy efficiency represents the things you can do with some amount of energy, and if you can do more with less, than it reduces the energy consumption.
Explanation:
The answer to this question is actually very simple. Imagine that you use only the half of the energy you produce, an efficiency of 50%. Lets say you need 5kJ, so you would need to produce 10kJ, because you can consume only the half. Now, imagine you increase the efficiency, you use exactly what you can generate, (efficiency of 100%). In this case, if you needed only 5kJ you would need to generate only 5kJ.
Students design an experiment to determine how much force is needed to move blocks of wood of different masses slowly across a lab table.
Which procedure should students include in their design?
A. conduct 5 trials, using a different scale to pull each block of wood
B. conduct 5 trials, pulling a different side of each block each time
C. conduct 5 trials, using a different table for each trial
D. conduct 5 trials, pulling each block of wood in the same way for each trial
What is potential energy?
Energy from chemicals
Energy that is stored
Energy from light
Energy of motion
Answer:
stored
Explanation:
P. E . = m g h
represents STORED energy in the form of the height * acceleration of gravity * mass
a 60-w light bulb radiates electromagnetic waves uniformly in all directions. at a distance of 1.0 m from the bulb, the light intensity is i0, the average energy density of the waves is u0, and the rms electric and magnetic field values are e0 and b0, respectively.
Answer:
Explanation:
1. If we increase the distance to twice it's original value, the light intensity is reduced by one-fourth, the light intensity would be:
I0/4
2. rms magnetic field is inversely proportional to distance, so the new rms magnetic field would be:
B0/2
3. average energy density is inversely proportional to the square of the distance, so the new average energy density is:
E0/4
The blackbody curve for a star named Zeta is shown below. What is the peak wavelength for this star?
impossible to tell because the scale for intensity is missing
0 nm
860 nm
3,010 nm
We are asked for the x coordinate of vertex
Here vertex is present somehow at 850-870nm
The most applicible answer should be 860nm
Option C is correct
You are using your phone to stream a movie. An hour into the movie, you notice that your phone is getting hot. What form of energy is the heat?
Answer:
Radio frequency energy. (Radiation)
Explanation:
the phone is getting hot due to large amount of used electricity. Geothermal energy is getting passed from the earth through the power lines from light and turns into electricity. this is what happens in a phone as well.
what you know about the laws of motion?
please help
What type of metal are conducting wires most often made of?
#16
Answer:
here
Explanation:
Copper is commonly used as an effective conductor in household appliances and in electrical equipment in general. Because of its low cost, most wires are copper-plated. You will often find electromagnet cores normally wrapped with copper wire
Determine the angular velocity ω of the telescope as it orbits around the Sun.
The human pupil, when maximally dilated, has a diameter of roughly 10 mm. How much more light does the primary mirror of the Magellan telescope (measuring 6 m in diameter) collect compared to the human eye
The amount of light collected by Magellan telescope with respect to human eyes is 1.13 x 10⁶ times that of human pupil.
Amount of light collect by human pupilThe amount of light that will pass through the given area of human pupil when maximally dilated is calculated as follows;
A = πd²/4
A = π(0.01)²/4
A = 2.5 x 10⁻⁵π m²
Amount of light collect by Magellan telescopeA = πd²/4
A = π(6)²/4
A = 9π m²
with respect to human eyes = ( 9π m²)/(2.5 x 10⁻⁵π m²)
= 1.13 x 10⁶ x human pupil
Thus, the amount of light collected by Magellan telescope with respect to human eyes is 1.13 x 10⁶ times that of human pupil.
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1. What is the energy of a photon of light with a wavelength (a) of 450 nm?
Answer:
2.76 eV
Explanation:
The Quanta of Light For example, a photon of blue light of wavelength 450 nm will always have 2.76 eV of energy.
Is it possible for an human body to be transparent or invisible?
Answer:
Yes, it is possible.
Explanation:
Hope this helps! :)
Answer:
it's possible since scientists have already progressed to making fully transparent & invisible human organs.
Use the circuit diagram to decide if the lightbulb will
light. Justify your answer
Any circuit diagram given the funda is same .
Look at the switch symbol in circuit (Mostly present after cell symbol) If there is a dot present the circuit is closed and current cannot be flowed so lightbulb won't light.If not present a dot then lightbulb will lightAnswer:
see picture
Sample Response: The lightbulb will light because this is a parallel circuit. Even though the switch is open in one branch, the branch the lightbulb is in forms a closed circuit, allowing the current to flow through the bulb.
Explanation:
The time required by 1KW heater to raise the temperature of 10 liters through 10 degree selsius is in the of 5 m
The time required by the 1 KW heater to raise the temperature of 10 L of water is 418.4 s
Data obtained from the questionPower (P) = 1 KW = 1000 WVolume of water = 10 LMass of water (M) = 10 × 1000 = 10000 gChange in temperature (ΔT) = 10 °C Specific heat capacity (C) = 4.184 J/gºC Time (t) = ?How to determine the timeQ = MCΔT
Q = Pt
Pt = MCΔT
Divide both sides by P
t = MCΔT / P
t = (10000 × 4.184 × 10) / 1000
t = 418.4 s
Complete question
What time is required for a 1kw heater to raise the temperature of 10 liters of water to 10 degree Celsius?
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Which of these elements would be the best
semiconductor?
O Ar
O Se
O Rh
O Po
Answer
Its PO
Explanation:
I got it right on Edge.
Water waves in a small tank are 6.6 m long. They travel at a speed of 2.9 m/s. What is the frequency of the water
waves?
Answer:
.439 Hz
Explanation:
Wavelength = 6.6 m
speed = 2.9 m/s
2.9 = 6.6 f
f = 2.9/6.6 = .439 Hz
A tuning fork consists of two metal prongs that vibrate at a single fre- quency when struck lightly. What will happen if a vibrating tuning fork is placed near another tuning fork of the same frequency
Resonance would occur when a vibrating tuning fork is placed near another tuning fork of the same frequency.
What is resonance?Resonance can be defined as a phenomenon in which a physical object is forced to vibrate due to the vibration of a second object at the same natural frequency of the first object.
This ultimately implies that, resonance is an increase in the amplitude of oscillation that only occurs when the frequency of a periodically applied force is equal to the natural frequency of a physical object such as a tuning fork, on which it's acting.
In conclusion, we can infer and logically deduce that resonance would occur when a vibrating tuning fork is placed near another tuning fork of the same frequency.
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A standing wave is a wave that remains in a constant position.
true or false
A mountain climber starts at the base of a mountain, climbs all the way to the peak, and then climbs back down to the base of the mountain. At which point is the climber's gravitational potential energy the greatest?
Base your answers to questions 11 through 13 on the information and diagram below and on your
knowledge of physics.
A ray of light with a frequency of 5.09 x 104 hertz traveling in medium X is refracted at point P.
The angle of refraction is 90°, as represented in the diagram.
Normal
Air
Refracted ray
Medium X
f = 5.09 x 1014 Hz
11. Calculate the wavelength of the light ray in air. [Show all work, including the equation and
substitution with units.]
12. Measure the angle of incidence for the light ray incident at point P.
13. Calculate the absolute index of refraction for medium X. [Show all work, including the equation and
substitution with units.]
Incident ray
11. The wavelength of the light ray in air is 0.589 x 10⁻⁶ m.
12. Angle of incidence for the light ray at point P is 43.23°.
13. The absolute index of refraction for medium X is 1.46
What is Snell's law?It states that the ratio of sine of angle of incidence and angle of refraction is equal to the refractive index of first medium to the second medium.
sini/sinr = n₁/n₂
11. The wavelength is related to the frequency as
λ = c/f
where c = 3 x 10⁸ m/s and frequency f = 5.09x 10¹⁴ Hz
Put the values, we get
λ = 3 x 10⁸/ 5.09x 10¹⁴
λ =0.589 x 10⁻⁶ m
Thus, the wavelength of the light ray in air is 0.589 x 10⁻⁶ m.
12. Given the angle of incidence is i, angle of refraction r =90° , n₂ = Refractive index of medium X = 1.46 and n₁ = Refractive index of air = 1
Substituting the values into Snell's law expression we get,
sin i= sin 90 x 1/1.46
i = 43.23 degrees
Thus, the angle of incidence is 43.23 degrees.
13. The refractive index is the ratio of speed of light in vacuum to the speed of light in the medium X.
n = c/v₂
If v₂ is the velocity of light in medium X, then
sin i / sin r = v₂/v₁
sin 43.23 / sin 90 = v₂/ 3 x 10⁸
v₂ = 2.055 x 10⁸ m/s
So, the refractive index be
n = 3 x 10⁸/2.055 x 10⁸
n = 1.46
Thus, absolute index of refraction for medium X is 1.46
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Is a cow a producer? Or a consumer or decomposer?
Answer:
cows a consumer
Explanation:
because it can make food by its own
Select the correct location on the image.
Answer:
Violet (Shortest Wave Length)
Explanation:
Violet waves have the highest frequencies. The highest frequencies have the shortest wave length.
How much of the electromagnetic spectrum can be seen with the human eye?.
The speed of sound in water is 1,492 m/s. A sonar signal is sent straight down from a ship at a point just below the water's surface and 7.5 s later the reflected signal is detected. How deep is the ocean beneath the ship?
Answer:
5595 m
Explanation:
The wave travels down (the depth) and the back up (the depth again)
this distance is 2 d
2 d = 1492 m/s * 7.5 s
2d = 11190 m
d = 5595 m
The half-life of Calcium-47 is 3.91 x 105 seconds. A sample contains 4.11 x 1076 nuclei. How much of the sample is left after 7.82 x 10 seconds?
2.57 x 1015 nuclei
5.14 x 1015 nuclei
1.03 x 1016 nuclei
2.06 x 1016 nuclei
Remember the formula
[tex]\\ \rm\Rrightarrow A(t)=A_o(0.5)^{\frac{t}{h}}[/tex]
h is half life[tex]\\ \rm\Rrightarrow A(7.82\times 10)=A(78.2)[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.5)^{\frac{78.2}{3.91\times 10^{5}}}[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.5)^{20\times 10^{-5}}[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.5)^{0.0002}[/tex]
[tex]\\ \rm\Rrightarrow 4.11\times 10^{76}(0.998)[/tex]
[tex]\\ \rm\Rrightarrow 4.10178\times 10^{76}[/tex]
Why no options matched?
That time given in end i.e 7.82×10
10 should contain some power to match our options .The number of nuclei of calcium-47 left after 7.82 x 10⁵s is 1.03 x 10¹⁶.
This can be found out using half life and laws of radioactive disintegration.
What are the laws of radioactive disintegration?
The Law of radioactive disintegration states the number of radioactive decay per unit time is proportional to the number of nuclei present in the sample initially.
So, ΔN/Δt = λN
Where, ΔN = number of radioactive nuclei decayed
Δt = time taken for decay
N = No of nuclei present initially
λ= decay constant
What is Half life?Half life is the time taken for the radioactive nuclei to reach half of its initial value.
Half life is given by
[tex]t_{1/2}[/tex] = λ/t
Given here, [tex]t_{1/2}[/tex] = 3/91 x 10.⁵s
N = 4.11 x 10¹⁶.
t = 7.82 x 10.⁵s
We see here that t = 2([tex]t_{1/2}[/tex])
Now, number of radioactive nuclei left undecayed in one half life is N/2
So number of nuclei left undecayed in 2 half lives will be 1/2(N/2) = N/4
So number of nuclei left in the sample will be N/4 = (4.11 x 10¹⁶.)/4
So Number of nuclei left in the sample = 1.03 x 10¹⁶.
Hence 1.03 x 10¹⁶is the correct answer.
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a) The velocity of a moving body is t2 - t metres per second after a time of t seconds. Find the displacement of the body at the end of 12 seconds if the initial velocity is 0 metres per second.
Explanation:
The integral of a velocity versus time function is a displacement versus time function
So we integrate,
[tex] {t}^{2} - t[/tex]
The integral of that is
[tex] \frac{1}{3} {t}^{3} - \frac{ {t}^{2} }{2} [/tex]
Plug in 12 for t,
[tex] \frac{1}{3} (12 {}^{3} ) - \frac{12 {}^{2} }{2} [/tex]
[tex]576 - 72 = 504[/tex]
So the displacement is 504 meters to the right.
vf = 12² - 12 = 132 m/s
a = vf' = 2t-1
at t =12 s,
a = 2(12)-1 = 23 m/s²
vf²=vi²+2ad (vi=initial velocity=0)
vf²=2ad
132² = 2 x 23 x d
d = 378.78 m
What is the role of pressure and dissolved gases in eruptions?.
Answer:
Explanation:
Magma contains dissolved gases, which provide the driving force that causes most volcanic eruptions. As magma rises towards the surface and pressure decreases, gases are released from the liquid portion of the magma (melt) and continue to travel upward, and are eventually released into the atmosphere.
also known as the dog star, what is special about sirius?
Drag force on a body increase with the increase in speed of the body.justify with one example from everyday experience
The drag force is the force that opposes the movement of a body through a fluid.
What is the drag force?The drag force is the force that opposes the movement of a body through a fluid. This occurs in cases such as when a car is moving through air.
Owing to the fact that drag force tends to slow down vehicles when they move at higher speed, vehicles that are meant for racing are streamlined to reduce the drag force.
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Which nuclear equation represents a spontaneous decay?.
Spontaneous fission is a nuclear equation represents a spontaneous decay.
Which nuclear equation represents a spontaneous decay?Spontaneous fission is another type of radioactive decay. In this process, the nucleus will split into two parts and free neutrons with the release of large amount of energy.
So we can conclude that spontaneous fission is a nuclear equation represents a spontaneous decay.
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When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it: Group of answer choices precession circumpolar motion retrograde motion ecliptic motion
I think you might be referring to this full question:
When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:
precessioncircumpolar motionecliptic motionretrograde motionrudeWhen a planet temporarily moves westward in the sky over the course of several weeks or months we call it retrograde motion.
What is retrograde motion?Retrograde motion is a movement that occurs when a planet rotates at a slower speed compared to another celestial body.
This type of slow movement (retrograde motion) gives us the illusion that the planet is retrograding regarding the other celestial body.
In conclusion, when a planet temporarily moves westward in the sky we call it retrograde motion.
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