Answer / Explanation:
To properly answer this question, let us define what a grain boundary is:
A grain boundary is the interface between multiple grains or crystals in a poly-crystalline material. They could also be refereed to as defects in the crystal structure and tend to decrease the electrical and thermal conductivity of structures.
Now, if we refer back to the question asked,
(a) The surface energy is grater than the grain boundary energy because surface atom have fewer bonds than atom along a grain boundary.
Consequentially, the lower the number of bonds formed, the higher the energy
(b) A higher angle grain boundary has higher misalignment and hence greater disruption of bonds (lesser number of bonds) than a small angle grain boundary. Therefore, a high angle grain boundary has higher energy.
Answer:
Explanation:
we know that 1 km =1000 m and 1 hour=3600 sec
therefore
15 km/hr=15*1000 m/3600 sec=4.167 m/s
Answer:
They do this by joining pieces of different Rock sequences together from different places in the whole world.
Explanation:
Geologic columns are basically an arrangement of rock layers whereby the newest rocks are at the top while the oldest rocks will be at the bottom. Thus, it is like a timescale that's used to find the age of rock formation on the earth around the world.
Answer: The given statement is True.
The proliferation of photosynthetic planktons results in harmful algal blooms. Due to this, the surface of the water body gets completely covered with algal bloom. This blocks the sunlight as it can not penetrate the water. Due to this, photosynthetic planktons are no more able to perform photosynthesis. This ultimately ends up depleting all oxygen from the body of water.
Thus, the given statement is true.
