The correct answer is the last one:
A and C are different elements, while D is an isotope of C.
In fact, A and C are different elements, because they have a different number of protons in the nucleus (A has 3 protons, while C has 4 protons). Instead, D and C are the same element (they both have 4 protons in the nucleus), but they are different isotopes since they have a different number of neutrons (D has 4 neutrons while C has 3 neutrons)
Answer:
The correct answer is "4.26 m".
Explanation:
Given:
Wavelength,

or,

Distance,

or,

Distance between the 1st and 2nd dark fringes,
As we know,
⇒ 
or,
⇒ 
By substituting the values, we get




The answer is approximately 2.998e+8
Here we know that mass of the person is 90 kg
His weight is given as 30 lbf
so here we can convert it into Newton as we know that
1 lbf = 4.45 N
Now from above conversion

now we can use this to find the gravity at this height



now we know that with height gravity varies as



so above is the height from the surface of earth
Answer:
the final speed of the rain is 541 m/s.
Explanation:
Given;
acceleration due to gravity, g = 9.81 m/s²
height of fall of the rain, h = 9,000 m
time of the rain fall, t = 1.5 minutes = 90 s
Determine the initial velocity of the rain, as follows;

The final speed of the rain is calculated as;

Therefore, the final speed of the rain is 541 m/s.