How long does it take long currents to complete their cycle around the world?

Which statement best describes the light that will cause emission of electrons from a given metal through the photoelectric effe

Sergio039 [100]

Answer:

light with a high enough intensity

Explanation:

4 0

2 years ago

An average person expends about 845 kilojoules of energy per hour of walking. Suppose a person eats 2 baked potatoes with butter

ExtremeBDS [4]

Answer:

$\large\boxed{2hours}$

Explanation:

You will need to use the conversion between food calories, calories and joules.

$1\text { nutritional calorie }= 1,000cal\\ \\ 1cal=4.184joule$

From a nutritional table (from the internet) you can obtain the amount of nutritional calories for each type macronutrient: carbohydrates, protein, and fat.

Macronutrient food calories

Carbohydrate 4 cal/g

Protein 4 cal/g

Fat 9 cal/g

To convert food calories to regular calories, mutiply by the conversion factor:

$1=1,000cal/\text{nutritional calorie}$

Macronutrient calories

Carbohydrate 4,000 cal/g

Protein 4,000 cal/g

Fat 9,000 cal/g

To convert regular calories to joules, multiply by the conversion factor:

$1=4.184 joule/1cal$

Macronutrient energy in joules

Carbohydrate 16,736 joule/g

Protein 16,736 joule/g

Fat 37,656 joule/g

Now you can multiply the grams of each macronutrient in one potato by its energy content:

Macronutrient energy/gram × grams = total energy

Carbohydrate 16,736 joule/g × 37 g = 619,232 joules

Protein 16,736 joule/g × 4.3 g = 71,968.8 joules

Fat 37,656 joule/g × 4 g = 150,624 joules

Total = 619,232 joules + 71,968.8 joules + 150,624 joules = 841,820.8 joules.

Since they are two potatoes, multiply by 2: × 841,820.8 joules = 1,683,641.6 joules.

Divide by 1,000 to convert to kilojoules = 1,683.64 kilojoules

Divide the total energy from the two potatoes by the energy that an average person expend per hour of walking (845 kilojoules of energy per hour):

$1,683.64kilojoules/845kilojouesl/hour=1.99hours\approx 2hours$

7 0

3 years ago

Two protons and two neutrons are released as a result of this reaction.

Murljashka [212]

Answer: The particle released in the given reaction is one alpha particle

Explanation:

In a nuclear reaction, the total mass and total atomic number remains the same.

For the given fission reaction:

$^{222}_{86}\textrm{Rn}\rightarrow ^A_Z\textrm{X}+^{218}_{84}\textrm{Po}$

To calculate A:

Total mass on reactant side = total mass on product side

222 = A + 218

A = 4

To calculate Z:

Total atomic number on reactant side = total atomic number on product side

86 = Z + 84

Z = 2

The isotopic symbol of unknown element is $_{2}^{4}\textrm{He}$ . Another name of helium atom is alpha particle.

Hence, the particle released in the given reaction is one alpha particle

3 0

3 years ago

Read 2 more answers

Aluminum, iron, copper, and oxygen are all examples of which of the following

ivolga24 [154]

The answer is elements.

7 0

3 years ago

!!NEED URGENT SCIENCE HELP!! Please help me with this I am so lost. I will mark you brainliest and like ur answer and rate it 5

Citrus2011 [14]

Answer:

1. D 2. C 3. B

Explanation:

1. The product is always what is being yielded from the equation, or what is created. Since both 4H2O and 3CO2 are created from the reactants, they are both products of the reaction.

2. The Law of Conservation of Matter states that matter cannot be created, nor destroyed. Therefore, C is not true because new atoms cannot be created in a reaction.

3. The second formula is balanced, but the first is not

5 0

2 years ago