ИДЗ1 Англ
.docxIndividual Task. LESSON 1. By
Answer the following questions:
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Formulate the Kirchhoff’s current law.
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What is the rule of sign’s definition in Kirchhoff’s current law in the equation?
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What another laws do you know that can help you to find unknown parameters of circuit?
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Formulate the Kirchhoff’s voltage law.
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According to Ohm’s law answer the question. What will be with voltage drop across the rheostat if we increase the resistance of rheostat when current is constant?
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What sign of e.m.f. will be in the right-hand side of equation of the Kirchhoff’s voltage law if arrows of e.m.f sources coincide with the direction of the contour tracing?
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What principles do you know that can help you to simplify the circuit or to find unknown parameters of the circuit?
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Look at the circuit on the video. Will the sign of I2 change in the equations if we changed the direction of this current?
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What is the essence of superposition principle?
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What is the essence of theorem of linear relationships?
Answers:
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The algebraic sum of all currents flowing into the node is equal to the sum of all currents flowing from the node.
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Currents that flow into the node are taken with a plus. The currents flowing from the node are taken with a minus.
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Laws that can help to find unknown parameters of circuit is Kirchhoff’s voltage law and Ohm’s law.
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The algebraic sum of the voltages on the circuit elements of the electric circuit is equal zero.
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Ohm’s law:
It is clear from the Ohm’s law, if you increase the resistance and do not change the current, then the voltage drop will increase.
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If the E.M.F. coincides in direction with the direction of the contour tracing, then the E.M.F sign is positive, otherwise negative.
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There are two principles that can help to simplify the circuit or to find unknown parameters of the circuit - superposition principle, reciprocity principle.
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If we change the direction of this current, then the sign of the current I2 changes to the opposite one.
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Superposition principle. The current in any branch of a linear electrical circuit including several sources can be represented as the sum of currents generated by each source.
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Theorem of linear relationships. When one parameter of а linear electric circuit (e.m.f, resistance, or current) is changed, any other two parameters of this circuit (currents or voltages) is bound by a linear relation of the form y = ax + b.