Answer:
C. 28.09 amu
Explanation:
The natural occurring element exist in 3 isotopic forms: namely X-28 (27.977 amu, 92.23% abundance), X-29 (28.976 amu, 4.67% abundance) and X-30 (29.974 amu, 3.10% abundance).
The atomic weight of elements depends on the isotopic abundance. If you know the fractional abundance and the mass of the isotopes the atomic weight can be computed.
The atomic weight is computed as follows:
atomic weight = mass of X-28 × fractional abundance + mass of X-29 × fractional abundance + mass of X-30 × fractional abundance
atomic weight = 27.977 × 0.9223 + 28.976 × 0.0467 + 29.974 × 0.0310
atomic weight = 25.8031871 + 1.3531792 + 0.929194
atomic weight = 28.0855603 amu
To 2 decimal place atomic weight = 28.09 amu
Look at the title of the graph, in small print under it.
Each point is "compared to 1950-1980 baseline". So the set of data for those years is being compared to itself. No wonder it matches up pretty close !
Answer:
Statement 2 is wrong
Explanation:
To check the statements in this exercise, let's describe the main properties of electromagnetic waves. Let's describe the characteristics
* they are transverse waves
* formed by the oscillations of the electric and magnetic fields
* the speed of the wave is the speed of light
with these concepts let's review the final statements
1) True. Formed by the oscillation of the two fields
2) False. They are transverse waves
3) True. Can travel by vacuum as they are supported by oscillations of the electric and magnetic fields
4) True. They all have the same speed of light
Statement 2 is wrong
Explanation:
It is given that,
A mass oscillates up and down on a vertical spring with an amplitude of 3 cm and a period of 2 s. It is a case of simple harmonic motion. If the amplitude of a wave is T seconds, then the distance cover by that object is 4 times the amplitude.
In 2 seconds, distance covered by the mass is 12 cm.
In 1 seconds, distance covered by the mass is 6 cm
So, in 16 seconds, distance covered by the mass is 96 cm
So, the distance covered by the mass in 16 seconds is 96 cm. Hence, this is the required solution.
Answer:
Stress = 4.67 * 10^-7 N/m²
Explanation:
Young's modulus of the material = Stress/Strain
Given
Young's modulus = 228 x 10^9 Pa
Stress = 106,483 Pa
Required
Strain
From the formula;
Strain = Stress/Young modulus
Strain = 106,483 /228 x 10^9
Stress = 4.67 * 10^-7 N/m²