Answer:
Explanation:
Some geologists favor convection currents in the mantle as the best explanation for plate tectonic movement. It is reasonable to assume that the heat radiated from the core creates convection currents in the mantle, and the mantle rocks begin to move plastically.
In any given wave, when the frequency of the wave doubles (f = 2f), which of the following other changes would also take place?
A The wavelength would double (λ = 2λ).
B The velocity would double (v = 2v).
C The wavelength would be half (λ = λ/2).
D The velocity would be half (v = v/2).
Answer:
The correct answer is -
B. The velocity would double (v = 2v).
C. The wavelength would be half (λ = λ/2).
Explanation:
A wave has a speed or velocity that is related to the wavelength of the wave and the frequency of the wave and this relationship can be represented by the following equation-
Wave velocity V = Wavelength (λ) * Frequency (f)
Frequency (f) = Velocity (V) / Wavelength(λ).
The frequency and wavelength are inversely proportional and frequency and velocity are directly proportional to each other.
So, if f = 2f then,
putting value in the formula,
2f = 2v/λ, which means, f = 2v and f = λ/2
when the frequency is doubled, the wavelength will be halved and velocity will be doubled.
How strong is the repulsive force exerted on two point charges that each carry 1.0 E-6 C of negative charge and are 0.30 meters apart?
Coulomb's Constant is 9.0 E9 N*m2/C2
Remember to identity all of your data, write the equation, and show your work.
F = Kq₁q₂/(r)²
K is a constant
R is the distance between them
F = 9.0 E9 × 1.0 E-6 × 1.0 E-6/(0.30)²
= 9.0E-3/0.30² = 9.0E-3/0.09 = 0.1 N
The electrostatic force of repulsion between two charges can be determined using Coulomb's law of electrostatic force. The force of repulsion between the point charges of magnitude 1 ×10 ⁻⁶ C separated by 0.30 m is 0.1 N.
What is Coulomb's law of electrostatic forces?According Coulomb's law of electrostatic forces, the force between two charges q1 and q2 separated by a distance of r meters is given by the expression:
F = K q1 q2/r²
Where, K is Coulomb's Constant equal to 9.0 ×10⁹ Nm²/C²
Given q1 = q2 = 1 ×10 ⁻⁶ C
r = 0.30 m
k = 9.0 ×10⁹ Nm²/C².
Then the electrostatic force of repulsion between the two point charges is calculated as follows:
F = 9.0 ×10⁹ Nm²/C² × 1 ×10 ⁻⁶ C × 1 ×10 ⁻⁶ C/ (0.30 m )²
= 0.1 N.
Therefore, the repulsive force exerted on two point charges that each carry 1.0 E-6 C of negative charge and are 0.30 meters apart is 0.1 N.
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In an immersion measurement of an odd-shaped metal object, the weight of the object is found to be 980 N when submerged in water. When it is submerged in a heavier Bromine liquid (density 3100 kg/m3), the object weighs 840 N. What is the volume of this object
Answer: [tex]0.00680\ m^3[/tex]
Explanation:
Given
The weight of the object, when submerged in the water is [tex]980\ N[/tex]
When it is submerged in the bromine liquid, it weighs [tex]840\ N[/tex]
Suppose,
[tex]\rho=\text{Density of object}\\\rho_w=\text{Density of water}\\\rho_b=\text{Density of bromine}\\V=\text{Volume of the object}[/tex]
for water,
[tex]\Rightarrow V(\rho -\rho_w)g=980\quad \ldots(i)[/tex]
For bromine
[tex]\Rightarrow V(\rho-\rho_b)g=840\quad \ldots(ii)[/tex]
Divide (i) and (ii)
[tex]\Rightarrow \dfrac{\rho-1000}{\rho-3100}=\dfrac{980}{840}\\\\\Rightarrow 840\rho -840\times 1000=980\rho-980\times 3100\\\\\Rightarrow 140\rho=(3038-840)\cdot 1000\\\\\Rightarrow \rho=15,700\ kg/m^3[/tex]
Put the density value in equation (i)
[tex]\Rightarrow V(15,700-1000)\cdot 9.8=980\\\\\Rightarrow V=\dfrac{100}{14,700}\\\\\Rightarrow V=0.00680\ m^3[/tex]
Suppose that the Department of Energy develops a new reversible engine that has a coefficient of performance (COP) of 4.0 when operated as a refrigerator and a COP of 5.0 when operated as a heat pump. What is its thermal efficiency when operated as a heat engine doing work
Answer:
η = 0.2 = 20%
Explanation:
The relationship between the thermal efficiency of a heat engine and the Coefficient of Performance (COP) of the corresponding Heat Pump is given as follows:
[tex]\eta = \frac{1}{COP_{HP}}[/tex]
where,
η = thermal efficiency = ?
[tex]COP_{HP}[/tex] = Coefficient of Performance of Heat Pump = 5
Therefore,
[tex]\eta = \frac{1}{5} \\\\[/tex]
η = 0.2 = 20%
The load across a 12 V battery consists of a series combination of three resistors 34 Ω, 42Ω, and 30Ω. What is the total resistance of the load? Answer in units of Ω. What is the current in the circuit? Answer in units of A.
Answer:
The total resistance is 106 Ω and the current in the circuit is 0.11 A.
Explanation:
Given that,
Voltage of the battery, V = 12 V
Resistors 34 Ω, 42Ω, and 30Ω are connected in series.
The total resistance is given by :}
R = 34 + 42 +30
= 106Ω
Let I is the total current in the circuit. Using ohm's law to find it such that,
[tex]I=\dfrac{V}{R}\\\\I=\dfrac{12}{106}\\\\I=0.11\ A[/tex]
Hence, the total resistance is 106 Ω and the current in the circuit is 0.11 A.
A metal with work function 1.17 eV is illuminated with light of wavelength 437 nm. What stopping potential is required for the photoelectrons
Answer: [tex]1.67\ V[/tex]
Explanation:
Given
Work function [tex]\phi =1.17\ eV[/tex]
The wavelength of the light is [tex]\lambda =437\ nm[/tex]
Energy associated with this wavelength is
[tex]E=\dfrac{hc}{\lambda}\\\\\Rightarrow E=\dfrac{1.99\times 10^{-25}}{437\times 10^{-9}}\\\\\Rightarrow E=4.553\times 10^{-19}\ J\\\\\Rightarrow E=2.841\ eV[/tex]
Stopping potential is
[tex]V=\dfrac{E-\phi }{e}\\\\\Rightarrow V=\dfrac{\left(2.841-1.17\right)e}{e}\\\\\Rightarrow V=1.67\ V[/tex]
a person is sitting on the last bench can see clearly see things written on book but cannot see them distinctly on board. what types of lens is this concave or convex
Answer:
I think concave
Explanation:
A 70 kg human body typically contains 140 g of potassium. Potassium has a chemical atomic mass of 39.1 u and has three naturally occurring isotopes. One of those isotopes, 40K (potassium), is radioactive with a half-life of 1.3 billion years and a natural abundance of 0.012 %. Each 40K (potassium) decay deposits, on average, 1.0 MeV of energy into the body.
What yearly dose in Gy does the typical person receive from the decay of 40K (potassium) in the body? Express your answer using two significant figures.
Answer:
Gy = 3.14x10⁻⁴ Gy
Explanation:
To get the dose in Gy we need to use the following expression:
Gy = E / m (1)
Where:
Gy: dose
E: energy absorbed per atom
m: mass of the human body.
We don't have the energy per atom, but we can calculate that by following the next procedure.
First, let's determine the number of atoms of potassium in our body. For that we need to determine the moles in the 140 g of potassium, with the molecular mass and then, use the avogadro's number:
moles = m/MM
moles = 140 / 39.1 = 3.58 moles
N° atoms = 3.58 * 6.02x10²³ atoms = 2.16x10²⁴ atoms of K.
The abundance of the ⁴⁰K is 0.012% so the atoms of this isotope would be:
N = 2.16x10²⁴ * (0.012/100) = 2.59x10²⁰ atoms of ⁴⁰K.
With this number, and the half life rate, we can determine the number of decay atoms in a year (λ) using the following expression:
λ = ln2 / t(1/2)
λ = ln2 / 1.3x10⁹ = 5.33x10⁻¹⁰ year⁻¹
This number, multiplied by the number of atoms:
R = 5.33x10⁻¹⁰ * 2.59x10²⁰ = 1.38x10¹¹ atoms/year
Now, each atom of K gives an average energy of 1 MeV, so with the atoms we have:
E = 1.38x10¹¹ * 1x10⁶ eV = 1.38x10¹⁷ eV
This value can be expressed in Joules so:
E = 1.38x10¹⁷ eV * (1 J / 6.24x10¹⁸ eV) = 0.022 J
Finally, we can use (1) to get the dose in Gy:
Gy = 0.022 / 70
Gy = 3.14x10⁻⁴ GyHope this helps
An alternating current is supplied to an electronic component with a warning that the voltage across it should never exceed 13 V. What is the highest rms voltage that can be supplied to this component while staying below the voltage limit in the warning
Answer:
9.2 V
Explanation:
The RMS value of an AC is the effective value of a varying voltage or current in DC, that is the equivalent value of the AC which produces the same effect as an DC. For example if a motor is supplied by a 9V RMS voltage, it will rotate as if the voltage applied was 9V DC.
The RMS value is given by:
RMS voltage = Peak voltage * 1/√2
Given that the maximum voltage should not exceed 13 V, this means that the peak voltage is 13 V. The maximum RMS voltage is:
RMS voltage = Peak voltage * 1/√2 = 13 * 1/√2 = 9.2 V
How can a tennis ball and a bowling ball have the same momentum ?
A tennis ball and a bowling ball can have the same momentum. This is because, it depends upon both the mass of object and velocity of object.
What is Momentum?Momentum can be defined as the mass in motion. All objects which have mass so, if an object is moving in space, then it has some amount of momentum which has its mass in motion. The amount of momentum which an object has depend upon two variables which include how much stuff is moving that is the mass of object and how fast the stuff is moving that is the speed.
A fast-moving tennis ball may have the same momentum as a slow-bowling ball. It is important to understand here that the momentum of an object which depends on the product of the mass and velocity of an object, but not the mass or the velocity alone.
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To increase the energy of an electromagnetic wave, which property should
you increase?
A. Shift
B. Frequency
o
C. Wavelength
D. Speed
Answer:
B. Frequency
Explanation:
A 620 nm light falls on a photoelectric surface and electrons with the maximum kinetic energy of 0.14 eV are emitted. (a) Determine the work function (in eV). eV (b) Determine the cutoff frequency of the surface (in THz). THz (c) What is the stopping potential (in V) when the surface is illuminated with light of wavelength 420 nm
Answer:
(a) The work function is 1.86 eV.
(b) The cut off frequency is 450 THz.
(c) The stopping potential is 1.16 V.
Explanation:
incident wavelength = 620 nm
Kinetic energy, K = 0.14 eV
According to the photoelectric equation
E = W + KE
where, W is the work function, KE is the kinetic energy.
(a) Let the work function is W.
[tex]W = E - KE\\W = \frac{h c}{\lambda }- KE\\W =\frac{6.63\times 10^{-34}\times3\times 10^{8}}{620\times 10^{-9}\times 1.6\times 10^{-19}}-0.14\\\\W =1.86 eV[/tex]
(b) Let the cut off frequency is f.
W = h f
[tex]1.86\times 1.6\times 10^{-19} = 6.63\times 10^{-34}\times f\\f = 4.5\times 10^{14} Hz =450 THz[/tex]
(c) Let the stopping potential is V.
[tex]E = W + eV\\\frac{6.63\times 10^{-34}\times 3\times 10^{8}}{420\times 10^{-9}\times 1.6\times 10^{-19}}=1.8 + eV\\\\V = 1.16 V[/tex]
Besides ethical considerations, what is another reason why Milgram’s experiment may be difficult to duplicate?
The first law of thermodynamics (which states that energy is conserved) does not specify the direction in which thermodynamic processes in nature can spontaneously occur.
a. True
b. False
Answer:
a. True
Explanation:
The law of conservation of Energy states that energy cannot be destroyed but can only be converted or transformed from one form to another. Therefore, the sum of the initial kinetic energy and potential energy is equal to the sum of the final kinetic energy and potential energy.
Mathematically, it is given by the formula;
Ki + Ui = Kf + Uf .......equation 1
Where;
Ki and Kf are the initial and final kinetic energy respectively.
Ui and Uf are the initial and final potential energy respectively.
The First Law of Thermodynamics is another way to describe the Law of Conservation of Energy. Typically, the First Law of Thermodynamics states that the change of internal energy of a system is equal to the sum of external work and heat spent on the system.
Mathematically, the First Law of Thermodynamics is given by the formula;
ΔU = Q − W
Where;
ΔU represents the change in internal energy of a system.
Q represents the net heat transfer in and out of the system.
W represents the sum of work (net work) done on or by the system.
Hence, the direction in which any thermodynamic process in nature can spontaneously occur isn't stated by the First Law of Thermodynamics.
Gold-198 is a radioactive isotope, and it has a half-life of about 2.5 days.
You have 100 grams of Gold-198. How many grams remain after 20 days?
3.125 grams
1.5625 grams
0.78125 grams
0.390625 grams
Answer: 0.390625 grams
Explanation:
A half-life of an element is the amount of time that it takes for half the mass of the element to decay.
Gold-198 having a half-life of 2.5 days therefore means that every 2.5 days, the mass is cut in half.
If there are 20 days, find out how many half-life periods there are:
= 20 / 2.5
= 8 periods
The half life is:
= Original mass * 0.5^number of half-life periods
= 100 * 0.5⁸
= 0.390625 grams
A 7.5 cm tall Aragorn action figure is placed 12.4 cm in front of a double convex lens. If the image of Aragorn is located 7.5 from the lens, what is the focal length of the lens?
Answer:
f = 4.67 cm
Explanation:
Here, we can use the thin lens formula, as follows:
[tex]\frac{1}{f}= \frac{1}{p}+ \frac{1}{q}\\\\[/tex]
where,
f = focal length of lens = ?
p = distance of object from lens = 12.4 cm
q = distance of image from lens = 7.5 cm
Therefore,
[tex]\frac{1}{f} =\frac{1}{12.4\ cm} +\frac{1}{7.5\ cm}\\\\\frac{1}{f} = \frac{1}{4.67\ cm}[/tex]
f = 4.67 cm
Which of the following is NOT a reason why humans sleep?
Sleep helps to restore and repair brain tissue.
Sleep restores and rebuilds memories.
Sleep provides a psychic safety valve to discharge unacceptable feelings.
During sleep, growth hormone is released, especially in children.
Answer and Explanation:
The answer is the second answer choice. This is because we humans can rebuild or build memories during the day, it doesn't have to happen via sleep.
The first answer choice IS a reason because you aren't working your brain as hard, so your brain has time to heal. A mouse study suggests that sleep helps restore the brain by flushing out toxins that build up during waking hours.
The third answer choice IS a reason because of the idea of Wish Fulfillment: Sigmund Freud suggested that dreams provide a psychic safety valve to discharge unacceptable feelings. The dream's manifest (apparent) content may also have symbolic meanings (latent content) that signify our unacceptable feelings.
The forth answer choice IS a reason because of the idea of Cognitive Development: Some researchers argue that we dream as a part of brain maturation and cognitive development.
#teamtrees #PAW (Plant And Water)
The lens labelled (B) has radius 16.5cm on the curved side. Using the shape of the lens to assign the sign of the radius, calculate the focal length of the lens. Give your answer with the correct positive or negative sign using the usual convention for lenses.
Answer:
convex f = 33 cm
concave f = -33 cm
Explanation:
In geometric optics the focal length of a lens is given by
[tex]\frac{1}{f} = ( n-1) \ (\frac{1}{R_2} - \frac{1}{R_1} )[/tex]
where n is the refractive index of the medium, R₁ and R₂ are the focal lengths on each side of the lens.
In this case one of the sides is flat so its focal length is infinite, if the lens is convex the focal length is positive, convergent lens and if it is concave the focal length is negative, divergent lens.
[tex]\frac{1}{f} = (n-1) \ \frac{1}{R}[/tex]
the refractive index of the glass is n = 1.5
let's calculate
1 / f = (1.5 -1) 1 / 16.5
1 / f = 0.03030
f = 33 cm
convex f = 33 cm
concave f = -33 cm
The diagram shows a toy car on a number line.
A line with arrowheads at both ends has ticks marks every 2 units. The tick marks for 0, 6, and 10 are labeled. A car sits above the tick mark for 2 with a dashed red line leading to the tick mark.
What is the position of the car?
–4
1
2
4
Answer: c.2
Explanation:
Answer:
The Answer is c. 2
Explanation:
I literally just got done with the quiz
Two electromagnetic waves are traveling through empty space. The wave with the greater wavelength is also characterized by _____.
a. the lower frequency
b. the higher frequency
c. the faster speed
d. the slower speed
A heater has resistance of 10 ohms. It operates at 120 volts. a. What is the current through the heater?
Answer:
I = 12 A
Explanation:
For this exercise we use the relationship that voltage is proportional to the product of current and resistance
V = I R
I = V / R
let's calculate
I = 120/10
I = 12 A
What are the functionssss of non-geostationary satellite?
Answer:
A communication system comprising a set of non-geostationary satellites provides communication links between ground stations and terminals, a communication link from a particular station via a satellite terminating at associated terminals in a limited geographical era including the station and providing a.Explanation:
Hopes this helps. Mark as brainlest plz!Geostationary satellites orbit around the Earth at the same rate as the Earth rotates so that the satellites are over the same spot on Earth all the time.
They are called geostationary due to their movement.
Geostationary satellites are a key tool for scientists to monitor and observe the Earth's atmosphere.
One long wire lies along an x axis and carries a current of 39 A in the positive x direction. A second long wire is perpendicular to the xy plane, passes through the point (0, 4.4 m, 0), and carries a current of 47 A in the positive z direction. What is the magnitude of the resulting magnetic field at the point (0, 0.80 m, 0)
Answer:
Explanation:
Magnetic field due to a long current carrying wire can be calculated as follows .
B = 10⁻⁷ x 2I / d where B is magnetic field , I is current .
The wire is along x -axis and the point is on y-axis at a distance of 0.8 m
Magnetic field at point of .8 m on y -axis
B₁ = 10⁻⁷ x 2 x 39 / 0.8
= 97.5 x 10⁻⁷ T .
Second wire is parallel to z-axis and passes through point on y-axis at a distance of 4.4 m . So the given point is at a distance of 4.4 - .8 = 3.6 m
Magnetic field
B₂ = 10⁻⁷ x 2 x 47 / 3.6
= 26.11 x 10⁻⁷ T .
Both these magnetic fields are perpendicular to each other so
Resultant magnetic field
B = √ ( 26.11² + 97.5² ) x 10⁻⁷ T
= √( 681.73 + 9506.25 ) x 10⁻⁷ T
= √( 10187.98) x 10⁻⁷ T
= 100.93 x 10⁻⁷ T .
Perhaps the greatest of the Greek astronomers, Hipparchus compiled the first catalog of stars, 49) accurately measured their positions, and defined the basic system of stellar brightnesses which we now call the magnitude system. A particular star in his catalogue has an apparent magnitude of 4 and an absolute -12. Determine the distance to the star.
Answer:
Explanation:
it would be 3 because ju divide 12 by 4
The tension in a pulley belt is 31 N when stationary. Calculate power in watts transmitted when the belt is on the point of slipping on the smaller wheel. the wheel is 379 mm diameter and the coefficient of friction is 0.3. The angle of lap is 1610. The wheel speed is 1,547 rev/min.
Answer:
P = 756.84 Watts
Explanation:
As the tension is stationary or innitial, T₀ = 31 N, the mean would be:
T₁ + T₂ / 2 = T₀ (1)
T₁ + T₂ = 2 * 31 = 62 N
Now, with the following expression we can determine the linear speed:
V = πWD (2)
W: angular speed of the wheel (rev/s)
D: diameter of the wheel (in meters)
W = 1547 rev/min * (1 min/60 s) = 25.78 rev/s
V = π * 25.78 * 0.379 = 30.695 m/s
We also know that:
T₁ / T₂ = exp (μθ)
T₁ = T₂ exp(μθ) (3)
We already have those values so replacing:
T₁ = T₂ exp(0.3 * 161 * π/180)
T₁ = 2.32T₂ (4)
We can now replace (4) in (1) like this:
T₁ + T₂ = 62 N
2.32T₂ + T₂ = 62
3.32T₂ = 62
T₂ = 18.67 N
Which means that T₁:
T₁ = 2.32(18.67)
T₁ = 43.33 N
Finally, the power can be determined using the following expression:
P = (T₁ - T₂)V (5) Replacing we have:
P = (43.33 - 18.67)*30.695
P = 756.84 WattsHope this helps
What is the function of an energy source?
1. Stop the flow of electricity
2.Open and close the circuit
3.Begin the flow of electricity
4.Slow down the electrons
When the palmaris longus muscle in the forearm is flexed, the wrist moves back and forth. If the muscle generates a force of 53.5 N and it is acting with an effective lever arm of 2.25 cm , what is the torque that the muscle produces on the wrist
Answer:
1.20Nm
Explanation:
Given data
Force= 53.5N
Perpendicular distance= 2.25cm= 2.25/100= 0.0225m
The expression for the torque is given as
Torque= Force* Perpendicular distance
Torque= 53.5*0.0225
Torque= 1.20Nm
Hence the toque produced is 1.20Nm
Two horizontal strings are attached to a block, resting on a frictionless surface as shown
below.A force of 100N pulls on one string. The block does not move. Find the value o
force, F on the other string
ON
Answer:
100N in the opposite direction
Explanation:
as the block is not moving, we can apply the formula f=ma where the total force is equal to the mass times accelaration, since the block is not moving, the net force is zero meaning that the other force is completely cancelling out the force of 100N, or to put it in a maths equation, 100-force=0 as the block is stationary. we can therefore assume that the force cancelling the 100N out is equal to it and therefore 100N in the opposite direction
How many spoonfuls of water did it take for your sponge to be 100% saturated?
Answer:
19
Explanation:
I legit did this and it took 19.
As part of a physics experiment, you carry a bathroom scale calibrated in newtons onto an elevator and stand on it. At rest, you check the scale and it reads 588 N. Then the elevator starts accelerating upward at 2.0 m/s2 and you check the reading again. Now what does the scale show
Answer: 708 N
Explanation:
Given
At rest, Elevator reads 588 N
When it starts moving upward at [tex]2\ m/s^2[/tex], apparent weight changes
i.e. weight can be given by
[tex]\Rightarrow W'=m(g+a)\\\Rightarrow W'=mg+mg\cdot \dfrac{a}{g}\\\\\Rightarrow W'=W\left(1+\dfrac{a}{g}\right)\\\\\Rightarrow W'=588\left(1+\dfrac{2}{9.8}\right)\\\\\Rightarrow W'=707.99\approx 708\ N[/tex]
The apparent weight is 708 N