Answer:
B. A dish of water is placed in the freezer and turns solid
Explanation:
it is a physical change because it can return to its original state by physical means. the other options are chemical changes because things like color change, bubbles or fizzing, and odor change all indicate a chemical change and cannot return to the original state it was in before.
Answer:
A=50mΩ
B≅50mΩ
Explanation:
A) To answer this question we have to use the Current Divider Rule. that rule says:
(1)
Itotal represents the new maximun current, 50mA, Ix is the current going through the 100 ohms resistor, and Req. is the equivalent resitor.
We now have a set of two resistor in parallel, so:
(2)
where R1 is the resitor we have to calculate, and R2 is the 100 ohms resistor (25 uA).
substituting and rearranging (2)
(3)
Now substituting (3) in (1).

solving this, The value of R1 is: 50mΩ
This value of R1 will guaranty that the ammeter full reflection willl be at 50mA.
Given that R2 (100ohm) it too much bigger than 50mΩ, the equivalent resistor will tend to 50mΩ
If you substitude this values on (2) Req. will be 49.97 mΩ.
Saturn's rings are made of billions of pieces of ice, dust and rocks. Some of these particles are as small as a grain of salt, while others are as big as houses.
Most volcanoes are found at convergent or divergent plate boundaries, but intraplate volcanoes are found in the middle of a tectonic plate.