Answer:
The correct option is: d. light isotopes move faster than heavy isotopes and thus are more readily evaporated
Explanation:
Evaporation is the process by which water present in liquid state changes into water vapor.
Since, oxygen has two isotopes: ¹⁶O (light isotope) and ¹⁸O (heavy isotope). Therefore, water molecule that consists of ¹⁶O is known as light water (H₂¹⁶O). Whereas, water molecule that consists of ¹⁸O is known as heavy water(H₂¹⁸O).
Since evaporation of heavier water molecules (H₂¹⁸O) is difficult than evaporation of light water molecules (H₂¹⁶O).
<u>Therefore, the water vapor formed by evaporation is rich in light water (H₂¹⁶O).</u>
Answer:
<u>Olivines an Pyroxene, and 5 to 10% of calcium oxides and aluminium oxides</u>.
Explanation:
- The upper mantle of the earth begins just 10 kilometers below the surface of the lithosphere and under the ocean about 35 km and ends to the lower mantel at 670 km.
- Here the temperature range from 200 to 900 degrees celsius, at the boundary is composed of 55% of olivines and 35% of pyroxenes, minerals such as garnet and spinal are also found.
- Lehmann discontinuity is which is an abrupt change caused by the p and s waves occurs at the depth of 220 km. In the upper mantel and lower crust, there exists a discontinuity called the Gutenberg discontinuity.
- Mantel forms the rigid liquid sphere on which the slabs move.