8TH GRADE PRACTICE
Physics Problems: Resistance and Ohm's Law, Grade 8
Conductor resistance, Ohm's law and rheostat.
Here the conditions and analysis of the solution can be read without an account. In the simulator, you need to collect the same analyzes yourself: “Given,” formulas, order of steps and answer.
Problem statements
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Problem #43
Resistance and Ohm's LawEvaluate the statement: One ohm is the resistance of the section in which a voltage of one volt creates a current of one ampere.
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The unit relates the readings of the ammeter and voltmeter through Ohm's law.
Answer
Problem #44
Resistance and Ohm's LawEvaluate the statement: the concept “Ohm's Law for a section” means: A physical quantity that characterizes the resistance of a conductor to the ordered movement of charges.
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The current versus voltage graph for an ohmic conductor is straight if the temperature does not change.
Answer
Problem #45
Ohm's lawA 6 ohm resistor maintains a voltage of 12 V. Find the current.
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Answer
Problem #46
Conductor resistance and rheostatEvaluate the statement: The resistance of a homogeneous conductor increases with length, decreases with cross-sectional area and depends on the material.
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A long, thin wire has more resistance than a short, thick wire of the same material.
Answer
Problem #47
Conductor resistance and rheostatEvaluate the statement: the concept of “Resistivity” means: A variable resistor that changes the length of the conductor included in the circuit and thereby regulates the current.
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Copper's low resistivity makes it suitable for wiring, while higher value alloys make it suitable for heaters.
Answer
Problem #48
Conductor resistanceA wire 10 m long and with a cross-sectional area of 2 mm² has a resistivity of 0.5 Ohm mm²/m. Find resistance.
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Answer
The theory behind these problems
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Formulas by topic
Look up symbols and units of measurement in the reference.