Answer:
momentum=mass×velocity
momentum =400kg×20m/s=8000kg.m/s
Since the electron dropped from an energy level i to the ground state by emitting a single photon, this photon has an energy of 1.41 × 10⁻¹⁸ Joules.
<h3>How to calculate the photon energy?</h3>
In order to determine the photon energy of an electron, you should apply Planck-Einstein's equation.
Mathematically, the Planck-Einstein equation can be calculated by using this formula:
E = hf
<u>Where:</u>
In this scenario, this photon has an energy of 1.41 × 10⁻¹⁸ Joules because the electron dropped from an energy level i to the ground state by emitting a single photon.
Read more on photons here: brainly.com/question/9655595
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If the net force on a block is zero, the block will move at constant velocity
Explanation:
We can answer this question by applying Newton's second law of motion, which states that the net force on an object is equal to the product between its mass and its acceleration:
(1)
where
is the net force on the object
m is its mass
a is its acceleration
In this problem, we have a block, and the net force on it is zero:
According to eq.(1), this also implies that
So, the acceleration of the block is zero.
However, acceleration is the rate of change of velocity of a body:
where 
is the change in velocity in a time of 
. Since the acceleration is zero, this means that 
, and therefore the velocity of the object is constant.
Learn more about Newton's second law:
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This is a list of well known characteristics of acids:
1) acids increase the concentration of hydronum ions ([H3O+]) when dissolved in water
2) acids taste sour
3) many are corrosive (the higher the acidity the higher the corrosive property)
4) when acids react with some metals produce hydrogen gas
5) acids conduct electricity (due to the presence of hydronium ions)
6) acids neutralize bases
7) acids combine with bases to produce water and salt
8) acids lower the pH of solutions.
They do not feel sticky to the touch. Bases fell slippery but there is not that property of sticky sensation about acids, although some highly concentrated strong acids have high viscosity. You cannot touch highly concentrated strong acids.
Would be A 1012 N/C because The magnitude of the electric field at distance r from a point charge q is E=k
e
q/r
2
, so
E=
(5.11×10
−11
m)
2
(8.99×10
9
N.m
2
/C
2
)(1.60×10
−19
C)
=5.51×10
11
N/C∼10
1
2N/C
making (e) the best choice for this question.
