what is the efficiency of an engine that does 80 j of work and exhausts 320 j of heat while taking in 400 j of heat ?
a. 10%
b. 20%
c. 80%
d. 25%

Refraction is the bending of light as it passes from one medium to another, causing objects to appear shifted or distorted when viewed through lenses.

The wave interaction that occurs as light passes from the air into the plastic lenses of the sunglasses is refraction. Refraction is the bending of light as it passes from one medium to another due to the change in its speed. This bending of light is what makes objects appear shifted or distorted when viewed through lenses.

Answer:

it is a nation wide crisis

Explanation:

Answer:

The internet is always growing

Explanation:

Answer:

there are no mutiple choices

Answer:

Redshift increases with distance

Explanation:

Edwin Hubble discovered a relation for distance and radial velocities of galactic nebulae from their redshifts i.e., when an object is moving away from earth the wavelength of light gets changed due to the Doppler effect.

He also found that two galaxies when further apart have a greater speed by which they are moving away from each other. This was used to prove the Big Bang theory laid down by Georges Lemaître.

Answer:

Aluminum ion is [tex]Al^{3+}[/tex]

Explanation:

Ions are formed due to the gain or loss of one or more electrons. There are two types of electric charges.

1. Positive charge

2. Negative charge

If an atom contains number of positive charges greater than the negative charges, its becomes positively charged. Also, if an atom contains number of negative charges greater than the positive charges, its becomes negatively charged.

We need to write the name of aluminium ion. The atomic number of Aluminium is 13. Its electronic configuration is, [tex]1s^22s^22p^63s^23p^1[/tex].

So, Aluminum ion is [tex]Al^{3+}[/tex]. Hence, this is the required solution.

The name of the aluminum ion is "aluminum ion" with a 3+ charge.

In chemistry, when an atom of aluminum loses three electrons, it becomes a positively charged ion known as the aluminum ion. Aluminum, as an element, is represented by the symbol Al and has an atomic number of 13, meaning it has 13 protons and 13 electrons in its neutral state.

When aluminum loses three electrons, it forms an aluminum ion with a 3+ charge. This happens because the number of protons (positive charges) remains the same, while the number of electrons (negative charges) decreases. The resulting positive charge on the ion signifies its ability to participate in various chemical reactions.

Aluminum ions play a crucial role in many industrial processes, particularly in the production of aluminum metal from its ore, bauxite. Additionally, they are essential in various chemical applications, including the manufacturing of aluminum-based products, catalysts, and electronics.

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Answer:

B. 22,22,23,23,22,22,23

Explanation:

The standard deviation is a measure of dispersion or variability of a data set. In order to determine the data set that has the smallest standard deviation, we shall investigate on the ranges of the data sets given. The range of a data set is simply the difference between the maximum and minimum values in a data set. A data set that has a smaller range also has a smaller standard deviation.

From the alternatives given, the data set given by alternative B has the smallest range and consequently the smallest standard deviation.

The maximum value is 23 while the minimum is 22. The range is 1.

The sun is the original source of solar energy, hydroelectric energy, food energy, coal energy, oil energy, and wind energy.

The sun is NOT the original source of nuclear energy. (b)​

Answer:

The answer is b. nuclear energy

Explanation:

Nuclear energy is a process through which electrical energy is generated by the disintegration of atoms from a material called uranium. The energy that uranium releases when its atoms disintegrate produces heat with which the water found in nuclear reactors is boiled to produce electricity.

Answer:

Any medium solid, liquid or gas is required for sound waves to travel.

Explanation:

A sound wave requires a medium to travel. Sound waves are mechanical waves that is why these waves require a medium to travel. Sound waves can travel through solids, liquids, and gases.

In solids, the particles of the medium are closely packed together as compared to liquids and gases. In liquids, particles are less tightly packed and almost negligible in gases.

Therefore sound waves produce vibration in the dense or solid medium. Denser the medium faster the sound waves travel. However sound waves can not travel through empty space.

Answer:

the answer is B just took the test!!

Explanation:

Answer:

Their atoms have identical mass.

Explanation:

Oxygen-17 and Oxygen-18 are both isotopes of Oxygen.

Oxygen has three isotopes, Oxygen- 16, Oxygen-17 and Oxygen-18.

Oxygen- 16 has 8 protons and 8 neutrons and a mass number of 16.

Oxygen-17 has 8 protons and 9 neutrons and a mass number of 17.

Oxygen-18 has 8 protons and 10 protons and a mass number of 18.

The three isotopes therefore have the same atomic number ( the number of protons) but different mass numbers.

Answer:

exothermic

Explanation:

energy is absorbed by the surroundings

Answer:

endothermic, because energy is absorbed from the surroundings

Explanation:

Answer:

specific heat

Explanation:

Specific heat is the amount of heat required to change the temperature of 1 gram of a substance by 1°C, and it is related to the chemical composition of the substance

[tex]F_{max}=7N\cdot1.75=\boxed{12.25N}[/tex]

Hope this helps.

r3t40

Answer:

Yes it is a solid

Explanation:

It just has unusual properties.

Does it float when you drop it? then it is not a gas.

Does it pour into any container as water does? Then it is not a liquid.

So it's a solid.

And it can change it's shape

Answer:

Yes, it is.

Explanation: Rubber band is ab elastic material which when stretched changes it's original shape.

The answer is:

The voltage of the source is 8.40 Volts.

To solve the problem, we need to use the Ohm's Law equation, which states that:

[tex]Voltage(Volts)=Current(Amps)*Resistance(Ohm)[/tex]

From the statement we know that:

[tex]Resistance=2.21\Omega\\Power=32W\\Current=3.8A[/tex]

Now, substituting and calculating we have:

[tex]Voltage(Volts)=Current(Amps)*Resistance(Ohm)[/tex]

[tex]Voltage(Volts)=3.8A*2.21\Omega=8.40V[/tex]

Hence, we have that the voltage of the source is 8.40 Volts.

Have a nice day!

Answer:

[tex]\frac{1}{2}[/tex]

Explanation:

[tex]\frac{5}{6} -\frac{1}{3} = \frac{15}{18} -\frac{6}{18}=\frac{9}{18} =\frac{1}{2}[/tex]

Answer:

1/2

Explanation:

we will take the LCM of denominators with is LCM (6,3)=6.

Now we shall make denominators equal no both sides. Since 5/6 already has 6 as denominator we shall multiply 2 with 3 to make denominators equal in 1/3 and so we also multiply 1 with 2. we get

1/3 × 1/2= 1/6 ×2/1=2/6

now 5/6-2/6=3/6=1/2

Explanation:

Newton's 1st law: An object in motion stays in motion, and an object at rest stays at rest, until acted upon by an unbalanced force.

Newton's 2nd law: Force equals mass times acceleration.

Newton's 3rd law: For every action, there is an opposite and equal reaction.

Answer:  C)  KClO3 → KCl + O2

Explanation:

the equation has an unequal amount of oxygen.

you can confirm because all the other equations are balanced so the answer is c

Answer:

[tex]KClO_{3}\rightarrow KCl+O_{2}[/tex]

(C) is correct option

Explanation:

Balanced equation :

In balanced equation, The number of atoms of each element in product side equal to the number of atoms of each element in reactant side.

The equation is not balanced in option C.

[tex]KClO_{3}\rightarrow KCl+O_{2}[/tex]

In this equation, The number of oxygen element in product side is not equal to the number of oxygen element in reactant side.

All equations are balanced.

Answer:

U

Explanation:

The first law of thermodynamics states that:

[tex]\Delta U = Q-W[/tex]

where

U is the internal energy of the gas, which represents the sum of the chemical and thermal energy stored in the atoms and molecules of the gas

[tex]\Delta U[/tex] represents the variation of internal energy

Q is the heat absorbed by the system

W is the work done by the system

So, the sum of the chemical and thermal energy stored in atoms and molecules is represented by U, the internal energy.

Answer:

U APEX

Explanation:

For this case we have that by definition, Newton's Second Law states that:

[tex]F = m * a[/tex]

Where:

F: It's the strength

m: It's the mass

a: It's the acceleration

According to the data we have to:

[tex]F = 8,480N\\a = 26.5 \frac {m} {s ^ 2}[/tex]

If we clear the mass of the formula we have:

[tex]m = \frac {F} {a}\\m = \frac {8,480} {26.5} = 320kg[/tex]

Answer:

The mass of the chart is 320kg

At the instant the second bulb is connected ...

... the brightness of the first bulb doesn't change

... the brightness of the second bulb changes from dark (no brightness) to equal to the first bulb

When the second 20 Ohm bulb is added in parallel, the bulbs becomes brighter

Adding a second, identical 20 Ohm bulb in parallel with the first one will have the effect of increasing the brightness of the bulbs.

In a series circuit, the total resistance increases as more resistors are added, which reduces the current flowing through the circuit. As a result, the bulbs would be dimmer in a series circuit.

However, when the second 20 Ohm bulb is added in parallel, the total resistance decreases, allowing more current to flow through the circuit. This increased current results in a higher brightness of the bulbs.

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Answer:

A measurement standard is defined as 'the exact quantity people agree to use for comparison'.

Explanation:

For the same type of quantity, there is a unit of measurement which is defined and adopted either conventionally or by law which is used as standard for measurement of that quantity.

This measurement standard is defined as 'the exact quantity people agree to use for comparison'.

For example, for length the standard unit of measurement is 'meter'.

Answer:

is an object system or experiment that bears a defined relationship to a unit of measurement of a physical quality

Answer:

Question 1 : is the rate of flow of electrons in electric current.

Question 2: represents the amount of pressure behind electron flow

Question 3: is the rate of doing work

Question 4: Power

Question 5: Both AC and DC are only possible in certain materials with atoms that will allow electron flow.

Both AC and DC involve the flow of electrons.

Question 6: The flow of electrons is not constant and forward; it changes direction back and forth.

Question 7: The flow of electrons is constant and only in a forward direction.

Question 8: The movement of electrons from one atom to another atom in a line results in a flow of electric current.

Question 9: Electrons flow from the metal with the lower affinity to the metal with higher affinity and electrical current is generated.

Answer:

a car parked in a garage

Explanation:

where would a parked car go ? its not even in motion lol

the answer is A

metallic bonds are formed between metal ions

Answer:

5.5 m/s

Explanation:

Assuming the bottle is initially stationary, we can write the law of conservation of momentum as follows:

[tex]p_i = p_f\\m_b u_b = m_b v_b + m_B v_B[/tex]

where

[tex]m_b = 0.4 kg[/tex] is the mass of the ball

[tex]u_b = 18 m/s[/tex] is the initial velocity of the ball

[tex]m_B = 0.2 kg[/tex] is the mass of the bottle

[tex]v_B = 25 m/s[/tex] is the final velocity of the bottle

[tex]v_b[/tex] is the final velocity of the ball

Solving for [tex]v_b[/tex],

[tex]v_b = \frac{m_b u_b - m_B v_B}{m_b}=\frac{(0.4 kg)(18 m/s)-(0.2 kg)(25 m/s)}{0.4 kg}=5.5 m/s[/tex]

Answer:

I beleive its B

Explanation:

If not then A but I'm positive its B

Answer:

Carbohydrate loading, commonly referred to as carb-loading or carbo-loading, is a strategy used by endurance athletes, such as runners, to maximise the storage of glycogen (or energy) in the muscles and liver. C. maximize glycogen stores.

Explanation:

Answer:

C. maximize glycogen stores.

Explanation:

magnitude.

scalars are units that has magnitude only

vectors have both magnitude and direction

Answer:

The answer is C, the magnitude.

Explanation:

Because force, acceleration and speed are all vector quantities. That is, to represent them not only reaches a number, but it takes an address, meaning, etc.

Instead a scalar magnitude (for example: temperature, mass) requiere for representation of a single value.

Answer:

Period

Explanation:

we know that

The period of a wave is the time required for one complete cycle of the wave to pass by a point.

Period is the time which is taken by a wave to complete one complete cycle.

Explanation:

The period can also be referred as the time period or the wave period. The period is relevant to the concept of wave and its propagation, which leads to the measurement of its travel, leading to establish the relation between the period and the frequency.

The S. I. unit for the period is seconds. The period is in inverse relationship of proportionality with the frequency, which is the number of cycles completed in a second.

Answer:

Its 2.5

Explanation:

She moves at 5 m per 2 seconds so she moves at 2.5 m per second

The provided data is insufficient to calculate Daniela's velocity. This is because velocity not only considers the speed but also the direction. Therefore, information on Daniela's direction during the race is necessary for an accurate calculation.

Unfortunately, the question does not provide sufficient information to calculate Daniela's velocity. Velocity is a measure that describes how much distance an object covers in a particular direction in a given amount of time. To calculate this, we must know not just the speed (distance/time) but also the direction of travel. Without the necessary data regarding Daniela's direction of movement during her race, we cannot provide a precise velocity value.

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