8TH GRADE PRACTICE
Physics Problems: Electric current, Grade 8
Sources, circuits, current and voltage.
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
The answer options are there to check against, and the walkthrough opens under each problem.
Problem #37
Electric current and circuitEvaluate the statement: Ordered motion of charged particles that exists in the presence of free carriers and an electric field.
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In metals, the carriers are electrons, and the conditional direction of the current is opposite to their directional movement.
Answer
Problem #38
Electric current and circuitEvaluate the statement: The concept “Current Source” means: The passage of current can cause heating, a magnetic field, chemical changes and an effect on living tissue.
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The source maintains a potential difference, a closed circuit provides a path for charges, and its circuit can be read according to the standard symbols of elements.
Answer
Problem #39
Electric currentThere are free electrons in a metal wire. What additional condition is necessary for a stable current?
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Answer
Problem #40
Current, voltage and devicesEvaluate the statement: A physical quantity equal to the charge passing through the cross section of a conductor per unit time.
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The ammeter is connected in series so that the same current passes through it as through the element under study.
Answer
Problem #41
Current, voltage and devicesEvaluate the statement: the concept “Electrical voltage” means: An ammeter is connected to the open circuit, and a voltmeter is connected to the ends of the selected section, taking into account the polarity.
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The voltmeter is connected in parallel to the section, since it compares the electrical states of its two points.
Answer
Problem #42
Electric current120 C of charge passed through the cross section of the conductor in 60 s. Find the current.
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Answer
The theory behind these problems
Work through the topic if a problem will not give in.
Formulas by topic
Look up symbols and units of measurement in the reference.