ИДЗ1 Англ

Individual Task. LESSON 1. By

Answer the following questions:

1. Formulate the Kirchhoff’s current law.

2. What is the rule of sign’s definition in Kirchhoff’s current law in the equation?

3. What another laws do you know that can help you to find unknown parameters of circuit?

4. Formulate the Kirchhoff’s voltage law.

5. 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?

6. 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?

7. What principles do you know that can help you to simplify the circuit or to find unknown parameters of the circuit?

8. Look at the circuit on the video. Will the sign of I2 change in the equations if we changed the direction of this current?

9. What is the essence of superposition principle?

10. What is the essence of theorem of linear relationships?

Answers:

1. The algebraic sum of all currents flowing into the node is equal to the sum of all currents flowing from the node.

2. Currents that flow into the node are taken with a plus. The currents flowing from the node are taken with a minus.

3. Laws that can help to find unknown parameters of circuit is Kirchhoff’s voltage law and Ohm’s law.

4. The algebraic sum of the voltages on the circuit elements of the electric circuit is equal zero.

5. 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.

6. 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.

7. There are two principles that can help to simplify the circuit or to find unknown parameters of the circuit - superposition principle, reciprocity principle.

8. If we change the direction of this current, then the sign of the current I2 changes to the opposite one.

9. 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.

10. 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.