Answer:
Photon of light
Explanation:
According to Bohr's model of the atom, electrons in atoms are found in specific energy levels. These energy levels are called stationary states, an electrons does not radiate energy when it occupies any of these stationary states.
However, an electron may absorb energy and move from one energy level or stationary state to another. The energy difference between the two energy levels must correspond to the energy of the photon of light absorbed in order to make the transition possible.
Since electrons are generally unstable in excited states, the electron quickly jumps back to ground states and emits the excess energy absorbed. The frequency or wavelength of the emitted photon can now be measured and used to characterize the transition. This is the principle behind many spectrometric and spectrophotometric methods.
<h3>Answer:</h3>
18.75 grams
<h3>Explanation:</h3>
- Half-life refers to the time taken by a radioactive material to decay by half of the original mass.
- In this case, the half-life of element X is 10 years, which means it takes 10 years for a given mass of the element to decay by half of its original mass.
- To calculate the amount that remained after decay we use;
Remaining mass = Original mass × (1/2)^n, where n is the number of half-lives
Number of half-lives = Time for the decay ÷ Half-life
= 40 years ÷ 10 years
= 4
Therefore;
Remaining mass = 300 g × (1/2)⁴
= 300 g × 1/16
= 18.75 g
Hence, a mass of 300 g of an element X decays to 18.75 g after 40 years.
The grams of aluminium extracted from 5000g of alumina is 2647 grams
<h3>Chemical formula of alumina:</h3>
Let's calculate the molecular mass of Al₂O₃
Al₂O₃ = 27 × 2 + 16 × 3 = 54 + 48 = 102 g/mol
Therefore,
102 g of Al₂O₃ = 54 g of aluminium
5000g of Al₂O₃ = ?
mass of aluminium produced = 5000 × 54 / 102
mass of aluminium produced = 270000 / 102
mass of aluminium produced = 2647.05882353
mass of aluminium produced = 2647 grams
learn more on mass here: brainly.com/question/14627327
Answer:
yes
Explanation:
The cell theory states that all biological organisms are composed of cells; cells are the unit of life and all life come from preexisting life. The cell theory is so established today that it forms one of the unifying principles of biology.
Answer:
Reason: Gravitational pull of the Moon
Explanation:
Weight of Garfield is 24 lbs on the Earth. He took a flight from the Earth to the Moon where the gravity is 1/6 of the gravity on the Earth.
But when reaches the Moon he found he weighed only 6 lbs. It is due to the gravitational pull of the Moon.
Mass of an object reamins the same at every location while its weight changes due to the change in acceleration due to gravity. It is equal (on Moon) to 1/6 the of acceleration due to gravity on the earth.
