Answer:
Density is an important physical property of matter. It reflects how closely packed the particles of matter are. When particles are packed together more tightly, matter has greater density.
Explanation:
The correct answer is option #4. The greatest obstacle to developing solar energy is large areas required to collect sufficient energy. Solar energy is the energy that is the sun is producing and being converted into thermal energy that can be used for everyone's daily lives.
Answer:
Convection occurs when thermal energy is transferred by the movement of fluid particles.
Explanation:
Transfer of heat energy by the movement of fluid particles is called convection. Convection takes place in liquids and gases due to kinetic energy. When heat is provided to liquids and gases they expand and move faster.
Molecules with higher kinetic energy become less dense and rise up to the surface of liquid, whereas molecules with lower energy move towards the bottom. This up and down movement of molecules causes convection currents in fluids.
