Solution: (i) Density (ii) thermal
Liquids at lower temperatures have greater density when compared to liquids at higher temperatures.This is because, at higher temperatures, molecules have greater kinetic energy and hence they are spaced farther apart, when compared to molecules at lower temperatures. Thus, the colder layers of liquids are heavier than the warmer layers, which causes then to move down due to gravity. For the same reason, the hotter layers move upwards through the liquid.
When a liquid is heated, the molecules closest to the heat source have greater energy, their density becomes less and they move upwards. The colder layers sink downwards. The layers of the liquid which were cold initially, get heated and they travel upwards. As the process repeats, convection currents are set up in the liquid.
These currents transfer the thermal energy derived from the source throughout the liquid. The process stops when the entire liquid is at the same temperature.
Thus, convection currents occur in liquids due to temperature and <u>density</u> differences. Convection currents transfer <u>thermal</u> energy throughout a fluid.
To answer this question do you need to know the formula to get the rate of change of acceleration (a=Δv/Δt; Δv= final velocity - initial velocity) and the formula to find the force of an object given a constant acceleration (F=m*a). Given these two formulas you can applicate them to solve for the mass of an object.
The answer is current.
Current in the context of an electrical circuit is the flow of charge. Current is a quantity that is physical and can be measured. Current is defined as the rate of the flow charge past a certain point in a circuit. Current is expressed in Amperes which is equal to 1 coulomb/1second.
so, question number 10 answer is 82 watts
