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3 years ago

How can describe electromagnetic waves with mechanical waves?

1 answer:

6 0

<span>Mechanical waves are mostly longitudinal waves. It means the constituents of the naterial through which the wave is moving are oscillating in the same direction as the wave itself.

In an electromagnetic wave the motion of the electric and magnetic fields is transverse to the direction of propogation of the wave. So the E, B and k vectors are perpendicular to each other. Also unlike a mechanical wave, an electromagnetic wave does not require a medium to travel. It can travel in completely empty space.

The matter wave or de Broglie wave comes from the wave particle duality of a quantum mechanical object such as an electron or an atom etc. This wave can also travel in empty space. Due to the strange nature of quantum mechanics, a quantum object manifests itself as a particle or a wave depending solely on the type of measurement or observation. So for example if one lets a stream of single electrons to fall upon 2 closely spaced slits then each electron would behave as a wave and lead to interference fringes on the screen behind the slits.</span>

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If i have 8 L of 0.25 M solution, how many miles of MgCl2 are present

qaws [65]

Answer:

2 moles

Explanation:

The following were obtained from the question:

Molarity = 0.25 M

Volume = 8L

Mole =?

Molarity is simply defined as the mole of solute per unit litre of solution. It is represented mathematically as:

Molarity = mole of solute/Volume of solution.

With the above equation, we can easily find the number of mole of MgCl2 present in 8 L of 0.25 M MgCl2 solution as follow:

Molarity = mole of solute/Volume of solution.

0.25 = mole of MgCl2 /8

Cross multiply to express in linear form

Mole of MgCl2 = 0.25 x 8

Mole of MgCl2 = 2 moles

Therefore, 2 moles of MgCl2 are present in 8 L of 0.25 M MgCl2 solution

4 0

3 years ago

Both kepler's laws and newton's laws tell us something about the motion of the planets, but there are fundamental differences be

I am Lyosha [343]

Answer: See description

Explanation:

Kepler's laws have three principal points:

1. planets orbit the sun in elliptical paths

2. the orbial period is related to the orbital distance by $T^{2} = d^3$

where T is the orbital period and d is the orbital distance, T is in years and d is measured in units of the earth sun distance.

3. planets closer to the sun move faster than planets far away from it.

Newton:

Newton discovered that there is a consequence to the gravity exerted by objects: mass, the heavier the planet, the more gravitational force it posseses ( thats why we orbit the sun)

with the gravitational force $F_{gravitational} =G \frac{Mm}{r^2}$ newton discovered the inverse-quadratic relationship between the distance of the planets and the acceleration exerted by the force one could exert on another.

Kepler's laws were mostly based on observed evidence with quantitative relationships between the mentioned variables. Newton's laws are based on calculus and symbolic equations. While Kepler's mode is basic, Newton took another step in and build a more general model for gravity (which was improved by general relativity later). In a nutshell Newton proved the scientific causes for Kepler's laws...

3 0

3 years ago

Car manufacturers are developing engines that use H₂ as fuel. In Iceland, Sweden, and other parts of Scandinavia, where hydroele

weeeeeb [17]

If the coulombs are supplied at 1.44 V, then 4.766 × 10¹¹ joules are produced.

(a) The reaction is

2H₂O + 2e⁻ → H₂ + 2OH⁻

According to the reaction, 2 moles of electrons flow per mole of reaction,

(b) Given

T = 25°C

Change Celsius into Kelvin

T = 25°C

= (25 + 273 ) K

= 298 K

<h3>What is Ideal Gas Law ?</h3>

It is expressed as

PV = nRT

Hence ,

n = $\frac{PV}{RT}$

= $\frac{(12)(3.5.10^{6} )}{(0.082057)(298)}$

= 1.7176 ×10⁶ mole

Now, From the given reaction we can say that ,1 mole of H₂ is produced by 2 moles of electron

Hence, 1.7176 × 10⁶ mole of H₂ is produced by

= 2 × 1.7176 × 10⁶ moles of electron

= 3.435 ×10⁶ moles of electron

We know that

charge = moles of electron × F

= (3.435 ×10⁶ × 96500) C

= 3.31 × 10¹¹ C

Voltage = $\frac{energy}{charge}$ = $\frac{J}{C}$

1.44 V = $\frac{energy}{3.31 . 10^{11} }$

Energy = 1.44 V × 3.31 × 10¹¹ C

= 4.766 × 10¹¹ Joules

Thus from the above conclusion we can say that, coulombs are supplied at 1.44 V, then 4.766 × 10¹¹ joules are produced.

Learn more about Fuel Cell here : brainly.com/question/16612142

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Disclaimer : The question given was incomplete on portal, Here is the complete question.

Question : Car manufacturers are developing engines that use H₂ as fuel. In Iceland, Sweden, and other parts of Scandinavia countries, where hydroelectric plants produce inexpensive electric power, the H₂ can be made industrially by the electrolysis of water.

a) How many moles of electrons flow per mole of reaction ?

b) How many coulombs are needed to produce 3.53X10⁶ L of H₂ gas at 12.0 atm and 25°C.

c) If the coulombs are supplied at 1.44 V, how many joules are produced?

8 0

2 years ago

When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II)

lesya692 [45]

Answer: The mass of lead deposited on the cathode of the battery is 1.523 g.

Explanation:

Given: Current = 62.0 A

Time = 23.0 sec

Formula used to calculate charge is as follows.

$Q = I \times t$

where,

Q = charge

I = current

t = time

Substitute the values into above formula as follows.

$Q = I \times t\\= 62.0 A \times 23.0 sec\\= 1426 C$

It is known that 1 mole of a substance tends to deposit a charge of 96500 C. Therefore, number of moles obtained by 1426 C of charge is as follows.

$Moles = \frac{1426 C}{96500 C/mol}\\= 0.0147 mol$

The oxidation state of Pb in $PbSO_{4}$ is 2. So, moles deposited by Pb is as follows.

$Moles of Pb = \frac{0.0147}{2}\\= 0.00735 mol$

It is known that molar mass of lead (Pb) is 207.2 g/mol. Now, mass of lead is calculated as follows.

$No. of moles = \frac{mass}{molar mass}\\ 0.00735 = \frac{mass}{207.2 g/mol}\\mass = 1.523 g$

Thus, we can conclude that the mass of lead deposited on the cathode of the battery is 1.523 g.

3 0

3 years ago

Arrange the following oxides in order of increasing acidity.

zmey [24]

Answer:

Based on the Modern Periodic table, there is an increase in the electropositivity of the atom down the group as well as increases across a period. On comparing the electropositivities of the mentioned oxides central atom, it is seen that Ca is most electropositive followed by Al, Si, C, P, and S is the least electropositive.

With the decrease in the electropositivity, there is an increase in the acidity of the oxides. Thus, the increasing order of the oxides from the least acidic to the most acidic is:

CaO > Al2O3 > SiO2 > CO2 > P2O5 > SO3. Hence, CaO is the least acidic and SO3 is the most acidic.

5 0

3 years ago