Answer: C) a&c
Explanation: Composite materials are the materials which are made up of the two or more material of different properties.They are usually having properties like high hardness,low in density,no dissolving into each other etc. Whiskers as a dispersing agent in composite materials are usually not preferred because they are expensive as well as they are not easy to disperse in the composite material.Thus option (c) is the correct answer.
Answer:
It is a well known fact that the earth rotates around the sun in an inclined axis which is approximately 23 degree. The inclined nature of earth axis causes variation in the solar heat received at any place on the earth surface. The hemisphere facing the sun due to this axial tilt, gets higher sun energy as compared to the opposite side. The hemisphere which faces the sun will experience summer whereas the hemisphere away from sun will experience winter.
In each of the hemisphere the polar areas will receive higher radiation and longer daytime during the summer season. However it has been observed that there is difference in radiation received at different areas of earth surface and radiated. The tropical areas have lower reflectance and thus a large part of incoming solar radiation have been absorbed along the tropics. The poles though have longer daytime during summer and hence greater solar radiation but due to high reflectance radiate more energy. Thus the tropical areas have surplus energy as compared to deficit energy areas of poles. This difference in energy creates a heat imbalance.
This net heat difference between poles and equator gives rise to a global circulation system leading to flow of heat from the net energy excess areas to deficit areas. This circulation takes place through atmosphere as well as oceans and different process of climate viz. evaporation, transpiration, rainfall, wind, convection, oceanic circulations etc work as tools of this system
Answer:
T=151 K, U=-1.848*10^6J
Explanation:
The given process occurs when the pressure is constant. Given gas follows the Ideal Gas Law:
pV=nRT
For the given scenario, we operate with the amount of the gas- n- calculated in moles. To find n, we use molar mass: M=102 g/mol.
Using the given mass m, molar mass M, we can get the following equation:
pV=mRT/M
To calculate change in the internal energy, we need to know initial and final temperatures. We can calculate both temperatures as:
T=pVM/(Rm); so initial T=302.61K and final T=151.289K
Now we can calculate change of U:
U=3/2 mRT/M using T- difference in temperatures
U=-1.848*10^6 J
Note, that the energy was taken away from the system.
