Answer:
Explanation:
As we know by radioactivity law
so here we will have
now we will have
now we also know that
The atomic number is the simply the number of protons in the atom. So in the first row with atomic number 2, the number of protons is 2.
If the atom has no charge, which I think you can assume for all of these, the number of electrons is equal to the number of protons. So the number of electrons is also 2.
The number of neutrons (which are the particles with no charge in the nucleus) is simply the mass number minus the atomic number i.e. 4 - 2 = 2.
The isotopic symbol is the symbol which is found on the periodic table of elements. There are 2 numbers associated which each element on the table. The larger is the mass number and the smaller is the atomic number. The atomic number or number of protons is what identifies the element. Looking at the periodic table ( https://sciencenotes.org/wp-content/uploads/2015/01/PeriodicTableOfTheElementsBW.pdf or https://simple.wikipedia.org/wiki/Periodic_table_(big) ), it can be seen that the element on the first row above with an atomic number of 2 is Helium with a symbol He. The number that is included with the name is simply the mass number which is 4 in this case, which tells us that this type of helium has 2 neutrons.
Another type (or isotope) of helium is Helium-3 which has one neutron.
Try the next row and post back if you have trouble with it
Answer:
The magnitude of the electric field be 171.76 N/C so that the electron misses the plate.
Explanation:
As data is incomplete here, so by seeing the complete question from the search the data is
vx_0=1.1 x 10^6
ax=0 As acceleration is zero in the horizontal axis so
Equation of motion in horizontal direction is given as
Now for the vertical distance
vy_o=0
than the equation of motion becomes
Now using this acceleration the value of electric field is calculated as
Here a is calculated above, m is the mass of electron while q is the charge of electron, substituting values in the equation
So the magnitude of the electric field be 171.76 N/C so that the electron misses the plate.
Answer:
the correct one is the first, the refractive index of the two materials must be the same
Explanation:
When a beam of light passes through two materials, it must comply with the law of refraction
n₁ sin θ₁ = n₂ sin θ₂
where n₁ and n₂ are the refractive indices of each medium.
In this case, it indicates that the light does not change direction, so the input and output angle of the interface must be the same,
θ₁ = θ₂ = θ
substituting
n₁ = n₂
therefore the refractive index of the two materials must be the same
When reviewing the answers, the correct one is the first
The horizontal force needed to start the calculator moving from rest is 1.5 N
What is Kinetic friction?
It is defined as a force that acts between moving surfaces.
The magnitude of the force will depend on the coefficient of kinetic friction between the two materials.
Here,
weight of calculator, N = 3 N
The coefficients of static frictions, µ (static) = 0.50
The coefficients of kinetic frictions, µ (kinetic) = 0.40
Now,
The horizontal force required = The static friction force
F = µ (static) * weight of calculator
F = 0.50 * 3.0
F = 1.5 N
Hence,
The horizontal force needed to start the calculator moving from rest is 1.5 N
Learn more about horizontal force here:
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