Answer:
C. molecules speed up as more thermal energy is added
Explanation:
The molecules will simply speed up as more thermal energy is added to the solid.
Thermal energy is a form of kinetic energy which is set in motion.
- Heat causes kinetic energy build up in a body.
- As the molecules of the solid gains heat, they will continue to increase in thermal energy.
- They are forced to start vibrating about their fixed point.
- Thereafter, when they have enough energy, they break free from the forces holding them.
- Therefore, they move from a state of rest to one with a very high kinetic energy where the molecules moves rapidly.
- This is why a solid will change to liquid and sometimes eventually gas
Answer:
a. Both wires have the same resistivity
Explanation:
For the resistance of a wire , following formula holds good .
R = ρ l / S , R is resistance , l is length , S is cross sectional area and ρ is resistivity of the material that the wire is made of. Resistance is dependent on length and cross sectional area but resistivity does not depend upon length or cross sectional area . It only depends upon the type of material.
If we replace copper wire with aluminium wire , then resistivity will change .
Hence , since the wire remains made of copper , resistivity will not change.
The hydropower plant and wind turbines both uses kinetic energy to produce mechanical power and convert the mechanical energy using a generator to an electrical energy. They both have the process to produce energy but they differ in the source the hydropower plant uses water to whit the wind turbines power plant uses wind. Therefore the answer is letter B.
