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3 years ago

What observation about light supported Einstein's theory?

1 answer:

5 0

In 1905 Albert Einstein had proposed a solution to the problem of observations made on the behaviour of light having characteristics of both wave and particle theory. From work of Plank on emission of light from hot bodies, Einstein suggested that light is composed of tiny particles called photons, and each photon has energy.

Light theory branches in to the physics of quantum mechanics, which was conceptualised in the twentieth century. Quantum mechanics deals with behaviour of nature on the atomic scale or smaller.

As a result of quantum mechanics, this gave the proof of the dual nature of light and therefore not a contradiction.

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A standard 1.00 kg mass is to be cut from a bar of steel having an equilateral triangular cross section with sides equal to 2.50

Elden [556K]

Answer:

The section of the bar is 2.92 inches.

Explanation:

Mass of the steel cut ,m = 1.00 kg = 1000 g

Volume of the steel bar = V = Area × height

Height of the of the section of bar = h

Area of Equilateral triangular = $\frac{\sqrt{3}}{4}a^2$

a = 2.50 inches

Cross sectional area of the steel mass = A

$A=\frac{\sqrt{3}}{4}(2.50 inches)^2=2.71 inches^2$

$V = 2.71 inches^2\times h$

Density of the steel = d = $7.70 g/cm^3$

$1cm^3 = 0.0610237 inches^3$

$d=\frac{m}{v}$

$\frac{7.70 g}{0.0610237 inches^3}=\frac{ 1000 g}{2.71 inches^2\times h}$

$h=\frac{ 1000 g\times 0.0610237 inches^3}{2.71 inches^2\times 7.70 g}$

h = 2.92 inches

The section of the bar is 2.92 inches.

3 0

3 years ago

The reaction for photosynthesis producing glucose sugar and oxygen gas is:

Anvisha [2.4K]

1.5 grams of glucose is produced from 2.20 g of CO₂.

To find the mass of glucose produced, first you must know the balanced reaction. For this, the Law of Conservation of Matter is followed.

The law of conservation of matter states that since no atom can be created or destroyed in a chemical reaction, the number of atoms that are present in the reagents has to be equal to the number of atoms present in the products.

So, in this case, the balanced reaction is:

6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the amounts of moles of each reactant and product participate in the reaction:

CO₂: 6 moles
H₂O: 6 moles
C₆H₁₂O₆: 1 mole
O₂: 6 moles

So, you know that 2.20 g of CO₂ react, whose molar weight is 44.01 g/mole. By definition of molar mass, 1 mole of CO₂ has 44.01 g. So, the number of moles that 2.20 grams of the compound represent is calculated as:

$moles of CO_{2} =2.20 grams*\frac{1 mole}{44.01 grams}$

moles of CO₂= 0.05 moles

Now you must follow the following rule of three: if by stoichiometry of the reaction 6 moles of CO₂ produce 1 mole of C₆H₁₂O₆, 0.05 moles of CO₂ produce how many moles of C₆H₁₂O₆?

$moles of C_{6} H_{12} O_{6} =\frac{0.05moles of CO_{2} *1 mole of C_{6} H_{12} O_{6}}{6moles of CO_{2}}$

moles of C₆H₁₂O₆= 8.33*10⁻³

Being the molar mass of glucose 180.18 g/mole, the mass that 8.33*10⁻³ moles of the compound represent is calculated as:

$mass of glucose =8.33*10^{-3} moles*\frac{180.18 grams}{1 mole}$

mass of glucose= 1.5 grams

Then, 1.5 grams of glucose is produced from 2.20 g of CO₂.

5 0

3 years ago

Breaking an object such as a mirror is an example of physical change, chemical change,physical reaction, chemical reaction

dangina [55]

Answer:

option A= Physical change

Explanation:

physical change:

" It is a change in which no new substance is formed"

Breaking of object like glass is the example of physical change because it is not change into another object. It effect the form of object but can not change the chemical composition.

Chemical changes:

" it is a change in which one substance is converted into new product through chemical reaction".

During the chemical changes the types and the number of atom remain same but their arrangement changed.

for example: burning of wood, baking of cake, digesting food, resting of iron etc.

Physical reaction:

" physical reaction occur during the molecular rearrangement. There is no chemical change occur"

In this type of changes no bonds are break to form new bonds, for example boiling point.

Chemical reaction:

" chemical reaction occur when molecules are chemically react with each others and bonds formation and breaking is also occur"

5 0

3 years ago

What is called when a paragraph studies data carefully

Zigmanuir [339]

Paraphrasing and summarizing

8 0

3 years ago

Read 2 more answers

The amount of energy that must be absorbed or lost to raise or lower the temperature of 1 g of liquid water by 1°C _____.

MatroZZZ [7]

Answer:

Explanation:

1 calorie = 4.184J/g×°C

This also happens to be the specific heat capacity of water, which is the amount of energy it takes to raise the temperature of 1mL of water by 1°C

6 0

3 years ago