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# كتاب الإمتحان physics تالتة ثانوي pdf - كتاب الشرح + كتاب الأسئلة + نموذج الإجابات ... Exam book third secondary physics pdf - explanation book + question book + answer form

Electric Current:
Electric current refers to the flow of electric charge in a conductor. It is measured in units called amperes (A) and denoted by the symbol "I." Electric current can be either direct current (DC), where the flow of charge is in one direction, or alternating current (AC), where the flow of charge periodically reverses direction.

Ohm's Law:
Ohm's law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points, while the resistance of the conductor remains constant. Mathematically, Ohm's law expressed as:

V = I * R

Where:
- V represents the voltage across the conductor,
- I represents the current flowing through the conductor, and
- R represents the resistance of the conductor.

This relationship allows us to calculate any one of the three variables (voltage, current, or resistance) if we know the values of the other two.

Electrical Measuring Devices:
1. Galometer: A galvanometer is an instrument used to detect and measure small electric currents. It works based on the principle of electromagnetic induction. Galvanometers are often used as the basis for more advanced measuring devices like ammeters and voltmeters.

2. Ammeter: An ammeter is a device used to measure the electric current in a circuit. It is connected in series with the circuit, allowing the current to pass through it. Ammeters have low resistance to minimize their impact on the circuit's current flow.

3. Voltmeter: A voltmeter is an instrument used to measure the voltage difference between two points in an electrical circuit. It is connected in parallel with the component or circuit being measured, allowing it to measure the potential difference across that component. Voltmeters have high resistance to prevent significant current flow through them.

4. Ohmmeter: An ohmmeter is a device used to measure the resistance of a component or circuit. It applies a known voltage to the component and measures the resulting current flow. Based on Ohm's law, the resistance can be calculated by dividing the applied voltage by the measured current.

These measuring devices are essential tools in electrical engineering and help in analyzing and troubleshooting electrical circuits.

Here are some physics-related questions on electric current, Ohm's law, and magnetic flux:

1. What is electric current?

2. How is electric current measured?

3. What is the difference between direct current (DC) and alternating current (AC)?

4. What is Ohm's law?

5. State Ohm's law equation and explain its components.

6. How does resistance affect the flow of electric current?

7. What is the unit of electrical resistance?

8. Can you give example of a material with high resistance and one with low resistance?

9. How does temperature affect the resistance of a conductor?

10. What is the relationship between voltage, current, and resistance according to Ohm's law?

11. What is magnetic flux?

12. How is magnetic flux calculated?

13. What is the unit of magnetic flux?

14. Explain Faraday's law of electromagnetic induction.

15. How does changing the magnetic field strength affect the magnetic flux?

16. What is the difference between magnetic flux and magnetic field?

17. Can you provide an example of a situation where magnetic flux changes?

18. How is magnetic flux related to the number of magnetic field lines passing through a surface?

19. What is the significance of magnetic flux in electric generators and transformers?

20. How is magnetic flux used in Gauss's law for magnetism?