3 Select the correct answer. What is a substance?
1 answer:
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(Missing question is: which of the following statements are true?)
a) <span>A battery does work on electric charges to bring them to a position of higher electric potential energy so that they can flow through a circuit to a lower potential energy --> TRUE
That's true: the battery does the work to move the charges to one end of its terminal thus creating a potential difference between the two terminals. Then, when it is connected to the circuit, charges start to flow to the terminal at lower potential (through the circuit)
b) </span><span>the potential difference between the terminals of a battery, when no current flows to an external circuit, is referred to as the terminal voltage --> FALSE
This is false: when no current flows, it is called e.m.f. (electromotive force)
c) </span><span>the internal resistance of a battery decreases with decreasing temperature
--> TRUE
In fact, the dependence of a resistance with the temperature is:
</span>![R=R_0[1+\alpha (T-T_0)]](https://tex.z-dn.net/?f=R%3DR_0%5B1%2B%5Calpha%20%28T-T_0%29%5D)
with
being generally positive, therefore the value of the resistance is proportional to T, and when T decreases, R decreases as well.
<span>d) a battery is a device that produces electricity by transforming chemical energy into electrical energy --> TRUE
</span><span>That's true: a battery uses chemical reactions to create a potential difference between the two terminals that can be exploited to make charges flowing through a circuit.
</span>
a) <span>A battery does work on electric charges to bring them to a position of higher electric potential energy so that they can flow through a circuit to a lower potential energy --> TRUE
That's true: the battery does the work to move the charges to one end of its terminal thus creating a potential difference between the two terminals. Then, when it is connected to the circuit, charges start to flow to the terminal at lower potential (through the circuit)
b) </span><span>the potential difference between the terminals of a battery, when no current flows to an external circuit, is referred to as the terminal voltage --> FALSE
This is false: when no current flows, it is called e.m.f. (electromotive force)
c) </span><span>the internal resistance of a battery decreases with decreasing temperature
--> TRUE
In fact, the dependence of a resistance with the temperature is:
</span>
with
<span>d) a battery is a device that produces electricity by transforming chemical energy into electrical energy --> TRUE
</span><span>That's true: a battery uses chemical reactions to create a potential difference between the two terminals that can be exploited to make charges flowing through a circuit.
</span>
Answer:
D. Frozen water is less dense than liquid water.
Explanation:
Titanic sank in the North Atlantic Ocean in the year 1912. There were more than 2000 passengers on board from which about 1500 died.
Frozen water that is ice has less density than liquid water. The density of ice is and the density of the water is
.
Due to this very slight difference in density, ice floats on water. Titanic, on the night of April 14, 1912, crashed into an iceberg around midnight which caused opening of 5 of its watertight compartments. The water filled into the ship and it eventually sank in.