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.
Steel tray because steel is an iron-carbon alloy
A.cooler and hotter rock rise but do not sink.
B.hotter and cooler rock sink but do not rise.
C.hotter rock rises and cooler rock sinks.
D.cooler rock rises and hotter rock sinks.
hotter rock rises and cooler rock sinks.
Answer: Option C.
<u>Explanation:</u>
The process that happens inside the surface of earth makes the rocks inside the surface to either expand or shrink in size because of the presence of heat inside the surface.
Heat rises and as the warmer rock gets further away from the super heated center of the Earth it begins to cool off and starts to sink back toward the super heated center of the Earth where it is reheated and the whole process starts over again. That is what a convection current is.
Answer:
2683.3N
Explanation:
According to coulombs law which states that "the force of attraction existing between two charge q1 and q2 is directly proportional to the product of the charges and inversely proportional to the square of the distance (d) between them. Mathematically |F|= k|q1| |q2| /d² where;
F is the force of attraction between the charges
q1 and q2 are the charges
d is the distance between them
k is the coulombs constant
Given |q1|= 38.9 × 10^-6C and |q2| = 27.6399×10^-6C d = 6cm = 0.06m
k = 8.98755 × 109 Nm² /C²
Substituting the given data's in the equation we have;
|F| = 8.98755 × 10^9×38.9×10^-6×27.6399×10^-6/0.06²
|F| = 9.66/0.06²
|F| = 9.66/0.0036
|F| = 2683.3N
The magnitude of the force will be 2683.3N
Note that the modulus of the charges changes negative value of q2 to positive value. The opposite signs of the charges doesn't affect the final calculation, it only tells the force of attraction or repulsion between the charges. Since they are unlike charges, they will attract each other in the field.
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