Answer:
1. A
2. B
3. B
4. A
5. B
6. C
7. D
8. C
9. C
10. C
Materials through which electricity pass easily are called conductors and material which do not transmit electricity and heat are insulators. Insulators doesn't allow the flow of electrons through it.
What are conductors ?Based on the conductivity of a material, there are three types of materials, namely conductors, semi-conductors and insulators. Conductors are conducting electricity and heat at room temperature. Semi conductors only conduct at higher temperatures or on doping.
The materials which does not conduct electricity and heat are called insulators. Hence, option b is correct. They will never allow the flow of electrons through them and thus why considered as insulators.
Whereas, conductors allow free electrons to flow through them easily. Among the groups , the group of good conductors are Iron, copper, silver, gold.
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Aluminum has an alpha value of 25 x 10^-6 1/degrees C. What is the change in
length of a 4850 cm wire at 2 degrees C when the temp increase to 55 degrees
C?
Answer:
0.25705 cm or 2.5705×10⁻³ m
Explanation:
Applying,
α = ΔL/(LΔT)................. Equation 1
Where α = coefficient of linear expansivity, ΔL = Increase in length, L = Original length, ΔT = Increase in temperature
make ΔL the subject of the equation
ΔL = α(LΔT)............... Equation 2
From the question,
Given: α = 10⁻⁶ C⁻¹, L = 4850 cm, ΔT = T₂-T₁ = (55-2) = 53 °C
Substitute these values into equation 2
ΔL = (10⁻⁶)(4850)(53)
ΔL = 0.25705 cm or 2.5705×10⁻³ m
а)
In figure below, assume that a 20-mm-diameter rivet joins the plates that are each 110 mm
wide. The allowable stresses are 120 MPa for bearing in the plate material and 60 MPa for
shearing of rivet. Find the followings. Express your final answer in N/mm².
110 mm
20-mm
P
(1) Determine the minimum thickness of each plate and largest average tensile stress in the
plates.
(6 marks)
Image of the plate is missing, so i have attached it.
Answer:
A) t = 7.854 mm
B) σ = 26.67 MPa
Explanation:
A) From shearing of rivet, formula for pressure is;
P = τ•A_rivets
Where;
τ is allowable stress
A_rivets is Area of rivet
We are given:
τ = 60 MPa
Diameter; d = 20 mm
A_rivets = πd²/4 = π × 20²/4 = 100π
Thus;
P = 60 × 100π
P = 6000π N
From bearing of plate material, we can calculate pressure as;
P = σ_b•A_b
We are given;
σ_b = 120 MPa
A_b is area of plate = 20t
Where t is the thickness
Thus;
6000π = 120 × 20t
t = 6000π/(120 × 20)
t = 7.854 mm
B) Largest average tensile stress is given by the formula;
σ = P/A
Where A = 110t - 20t
A = 90t
A = 90 × 7.854
Thus;
σ = 6000π/(90 × 7.854)
σ = 26.67 MPa
the statement that current is equal to the voltage difference divided by the resistance is known as what
Answer:it is known as (Ohm's law)
Explanation:
Explain the mode of operation of x-ray
Answer:
If x-rays get in touch with our body tissues, they create a picture of a metal film. The high energizing rays are unable to penetrate soft tissue, such as skin and organs and travel through the laser. The places where the x-rays pass soft tissues are Black areas of an X-ray.
Answer:
Explanation:
Mode of Operation: In the X-ray tube a Low voltage high p.d is applied between the hot cathode and the anode. Electrons are emitted from the cathode and are accelerated to an extremely high speed. ... They are produced by increasing the p.d. between the cathode and anode.
Un corredor hace los 400 metros lisos en 50 seg. Calcula la velocidad en la carrera.
Answer:
8 meters/second
Explanation:
Rate x Time = Distance
R x T = D
R x 50sec = 400meters
R x 50sec/50sec = 400meters/50sec
R = 8meters/sec
The amount of force needed to cause an object to accelerate depends upon
A.
the object's mass and the net force acting upon it.
B.
the object's volume and the net force acting on it.
C.
the object's mass and volume.
D.
the object's speed and direction.
someone pls help
Answer:
A
Explanation:
I have read the information
What are 3 facts you learned about the periodic table:
Answer: the rarest element is Francium. J is not on the periodic table. also Dmitri Mendeleev proposed the periodic table.
Explanation: Kinda looked the last one up.
If a proton were released in the electric field above, what direction would it move?
Answer:
d because the proton would move towards the negative plate
Explanation:
what determines the strength of a base?
The higher the dissociation constant the stronger the acid or base. Since electrolytes are created as ions are freed into solution there is a relationship between the strength of an acid, a base, and the electrolyte it produces. Acids and bases are measured using the pH scale.
Aplane monochromatic electromagnetic wave with wavelength λ = 2.2 cm, propagates through a vacuum. its magnetic field is described by
where bx = 3.1 x 10-6 t, by = 3.4 x 10-6 t, and i-hat and j-hat are the unit vectors in the +x and +y directions, respectively.
1) what is f, the frequency of this wave?
2) what is i, the intensity of this wave?
3) what is sz, the z-component of the poynting vector at (x = 0, y = 0, z = 0) at t = 0?
4) what is ex, the x-component of the electric field at (x = 0, y = 0, z = 0) at t = 0?
5) Compare the sign and magnitude of Sz, the z-component of the Poynting vector at (x=y=z=t=0) of the wave described above to the sign and magnitude of SIIz, the z-component of the Poynting vector at (x=y=z=t=0) of another plane monochromatic electromagnetic wave propagating through vaccum described by: ω where BIIx = 5.5 X 10-6 T, BIIy = 3.4 X 10-6 T, and i-hat and j-hat are the unit vectors in the +x and +y directions, respectively.
siiz < 0 and magnitude(siiz) ≠ magnitude(sz)
siiz < 0 and magnitude(siiz) = magnitude(sz)
siiz > 0 and magnitude(siiz) ≠ magnitude(sz)
siiz > 0 and magnitude(siiz) = magnitude(sz)
Answer:
a
Explanation:
Which quantity does not change when there is an increase in temperature?
Answer:
But Mass of solids does not depend upon the temperature because it is matter contained in the solids.
Explanation:
The mass is the quantity which does not change when there is an increase in temperature.
What is mass?A tangible body's mass is the amount of matter it possesses. It's also a metric of inertial, or the resistance to velocity when a net force is exerted.
The quantity does not change when there is an increase in temperature is mass because it is matter that makes up solids, their mass is unaffected by temperature.
Thus, the mass is the quantity which does not change when there is an increase in temperature.
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A block attached to an ideal spring oscillates horizontally with a frequency of 4.0 Hz and amplitude of
0.55 m. The spring constant is 75N/M
What is the mass of the block?
Answer:
.12kg
Explanation:
khan academy
What are political obstacles keeping wind turbine from being used?
Explanation:
Turbines might cause noise and aesthetic pollution.
Although wind power plants have relatively little impact on the environment compared to conventional power plants, concern exists over the noise produced by the turbine blades and visual impacts to the landscape.
The inflexibility, variability, and relative unpredictability of wind power as a means for electricity production, are the most obvious barriers to an easy integration and widespread application of wind power." Thus, the uncertainty of the wind requires a system that is always available to replace all the electrical output created by the wind turbine system. In other words, it is too expensive to have wind turbines lying around that don't do anything.
Which one of the following is not a symbol used in chemical equations?
A. (d)
B. (g)
C. (aq)
D. (s)
O
Answer:
b,
Explanation:
i think but dont take my word for it
Drag each label to the correct location on the image. Not all labels will be used, Classify the sides of the mountain range based on the direction of the prevailing winds leeward side windward side Jake-effect side
WILL MARK BRAINLIEST!
Answer:
The picture didn't go thruuuuuuu
Answer:
hi
Explanation:
hi
Convert 0.0375 kg to g
Answer: 37.5 g
Explanation: you multiply 0.0375 by 1000 which equals 37.5
Answer:
0.0375 kilograms are equal to 37.5 grams
What does the potential energy diagram of a chemical reaction tell you?
O A. Whether atoms are being created or destroyed
O B. Whether the reaction is endothermic or exothermic
C. Whether there are more reactants or products
D. Whether the law of conservation of matter is being obeyed
Answer:
B
Explanation:
I'm learning about this now actually and it can be a little confusing but it would be endothermic or exothermic. if endothermic the products have less energy than the reactants and if exothermic products have more energy than reactants
Which of the following statements correctly describe the various applications listed above?
a. None of these technologies use radio waves.
b. None of these technologies use lower-frequency microwaves.
c. None of these technologies use higher-frequency microwaves.
d. None of these technologies use infrared waves.
e. The radiation emitted by some wireless local area networks has the shortest wavelength of all the technologies listed above.
f. All these technologies emit waves with a wavelength in the range 0.10 to 10.0 cm.
g. All the technologies emit waves with a wavelength in the range 0.01 to 10.0 km.
Answer:
The answer is "c,d,e, and g".
Explanation:
The correct choices can be defined as follows:
Higher-frequency microwaves aren't used in any of these systems.Infrared waves aren't seen in each of these technologies.Its shortest wavelength of all of the technologies listed is the above radiation generated by certain wireless networks.These devices all produce waves of wavelengths ranging from 0.10 to 10.0 cm.The ratio of carbon 14 to nitrogen-14 in an artifact is 13. Given that the half-
life of carbon-14 is 5730 years, how old is the artifact?
A. 17,190 years
B. 22,920 years
C. 11,460 years
D. 5730 years
Answer:
The half-life of 14C is 5703 years.
If a body of mass 2 kg is moving with a velocity of 30 m/s, then on doubling its velocity the momentum becomes______.
a-60kgm/s
b-120kgm/s
c-90kgm/s
D-30kgm/s
You throw a ball straight up. Compare the sign of the work done by gravity while the ball goes up with the sign of the work done by gravity while it goes down.
a. Work is + on the way up and + on the way down
b. Work is + on the way up and - on the way down
c. Work is - on the way up and + on the way down
d. Work is - on the way up and - on the way down
Answer:
c. Work is - on the way up and + on the way down
Explanation:
Work done is given as the product of the applied force and the displacement of the object.
Work done = F x d
Work done = mg x d
where;
g is acceleration due to gravity = 9.8 m/s²
When the ball goes up, it moves against the force of gravity which tends to pull every object downwards. Since the ball moves against gravity, the work done is negative.
Also, when the ball goes down, it moves in the direction of gravity which acts downwards. Since the ball moves in the same direction as gravity, the work done is positive.
The correct option is "C. Work is negative (-) on the way up and positive (+) on the way down"
Descriptions of the sky at various locations on Earth
What is the frequency of microwaves of wavelength 3 cm?
Give your answer to the
nearest GHz and without units.
Answer:
10 GHz
Explanation:
Applying,
v = λf.................... Equation 1
Where v = speed of microwave, λ = wavelength, f = frequency.
make f the subject of the equation
f = v/λ................ Equation 2
Note: Microwave is an electromagnetic wave, and all electromagnetic wave have the same speed, which is 3×10⁸ m/s
From the question,
Given: λ = 3 cm = 0.03 m
Constant; v = 3×10⁸ m/s
Substitute these values into equation 2
f = 3×10⁸/(0.03)
f = 10¹⁰ Hz
f = (10¹⁰/10⁹) GHz
f = 10 GHz
The specific heat of hexane is 2.26 J/gºC. If 11,500 J of heat is added to
a 315 g sample of hexane, then how much is the increase in the
temperature of the sample?
Answer:
16.2
Explanation:
Yes
A horizontal wire supports it weight in a 0.001T magnetic field, oriented orthogonally to the wire. This is due to current running from left to right in the wire. Calculate the current through this wire that will just support the weight of the wire (over the length of the wire). The length of the wire is 0.5 m, and the mass of the 0.5 m section is 50 g. [give your answer in units of Amps]
Answer:
Explanation:
Force on a current carrying wire in a magnetic field
= B i L where B is magnetic field , i is current and L is length of the wire .
Putting in the given values in the question
force on a current carrying wire in a magnetic field = .001 T x i x .5 m
5 x 10⁻⁴ i N .
weight of the wire = .050 kg x 9.8 m/s²
= .49 N .
For equilibrium
5 x 10⁻⁴ i = .49
i = 980 A .
which of the following changes will increase the frequency of an oscillating pendulum?
a. an increase in the mass of the pendulum.
b. an increase in the initial height of release.
c. an increase in the length of the rope.
d. more than one of the above
e. none of the above
explain your answer in your own words.
NO LINKS.
Answer:
b (i think)
Explanation:
Which statement correctly describes the location, charge, and mass of the
neutrons in an atom? *
The neutrons are outside the nucleus, have no charge, and have no mass.
The neutrons are inside the nucleus, have no charge, and have mass.
The neutrons are outside the nucleus, have a negative charge, and have no mass.
The neutrons are inside the nucleus, have a negative charge, and have mass.
What is the total number of protons, neutrons, and electrons in a cadmium, Cd,
atom that has a mass number of 112? *
The neutrons are inside the nucleus, have no charge, and have mass.
Future space stations could create an artificial gravity by rotating. Consider a cylindrical space station that rotates with a period of 28 seconds about its axis. Astronauts walk on the inside surface of the space station, and they experience an Earth-like gravitational acceleration of 9.8 m/s2. What is the diameter of the space station?
510m
145m
660m
390m
Answer:
P = 2 pi R / v period of space station
F / m = v^2 / R centripetal force per unit of mass
So F / m = 4 pi^2 R^2 / (P^2 * R) = 4 pi^2 R / P^2
Also, F / m = 9.8 m/s^2 earth's gravitational attraction
So 9.8 = 4 pi^2 R / P^2 or R = 9.8 P^2 / 4 * pi^2) = 195 m
Or D = 2 R = 390 m the diameter required
This picture represents the electric field diagram between two particles with static charges. Do the two particles have the same charge? If the particles are free to move, what affect will the two particles have on each other? If a third particle was added to this field with a positive charge, what would it be attracted to? If an uncharged particle was placed between A and B, which way would it move?
Answers:
No, They will attract each other, B, and neither direction
Explanation:
Since the two already presented particles in the diagram represent both opposing charges due to the direction of the arrows (the arrows facing away from the particle shows a positive charge and the particles facing towards the particle show a negative charge), not only because of this but as the arrows between the particles show an attracting magnetic field, then it can be concluded that the particles will attract to each other and if another particle was introduced into the diagram of a positive charge, then it would attract to the negatively charged particle. If you have any questions or need further explanation, please comment below. E2021, have a great day.
Answer:
No, They Will Attract Each Other, B, and Neither Direction
Explanation: Im an edge student
The hydrogen atom, changing from its first excited state to its lowest energy state, emits light with a wavelength of 122 nm. That is in the far ultraviolet. The sodium atom, which like hydrogen has one electron that gets excited outside a core of 10 other electrons, emits light at 589 nm making a similar transition from its first excited state to its lowest state. Which of these statements would be true about the sodium and hydrogen atoms and their spectra? THERE IS MORE THAN ONE CORRECT ANSWER
a. There would be other series of spectral lines ending on the first excited states of both atoms.
b. There would be a series of spectral lines in sodium with the longest wavelength one at 589 nm.
c. There would be a series of spectral lines in hydrogen with the longest wavelength one at 122 nm.
d. The hydrogen atom binds its electron more tightly than the sodium atom does, and would require more energy to remove its electron completely.
Answer:
c. There would be a series of spectral lines in hydrogen with the longest wavelength one at 122 nm.
d. The hydrogen atom binds its electron more tightly than the sodium atom does, and would require more energy to remove its electron completely.
Explanation:
The hydrogen atom which changes from the excited state to the lower ground state, it emits light having a wavelength of 122 m. And the sodium atom also gets excited and emits light at 589 nm when it moves from the 1st excited state to the lowest excited state.
Therefore, when the electrons jumps from the 1st excited state to the ground state, only one wavelength is observed as there is only one transition.
The hydrogen atom will bind the electron tightly but the sodium atom does not and would require more energy to remove the electron the electron completely as the binding energy is higher when the electron is closer to the nucleus.