Test 1 will be based on chapter 20. There will be 10 multiple choice questions and 2 problems to answer. Duration of the test is one hour. There will be conceptual questions as well as quantitative questions. You will need to bring a scientific calculator. You can bring one page equation sheet and there should be equations only with some simple explanations.

1. Know about electric charges and how they interact with each other. Charge of electron and proton.

2. What is meant by charging? Charging by friction and charging by contact.

3. polarization of electric charges - local (in insulators) and global (in conductor) difference between electric conductors and insulators. Understand how the atomic model is used to explain them, free (free to move) electron inside a conductor and tightly bound electrons in insulators.

4. Calculating the electric force between two charges. Use of Newton’s third law for the electrical interaction.

5. Variation of electric force over the distance between two charges. Variation of electric force with the magnitude of two charges.

6. Calculating the electric force acting on a charge due to more than two charges. Use of the “principle of superposition” to calculate the force. Use of vectors.

7. Electric field. Definition of the electric field with respect to a unit positive test charge.

Vector nature of the electric field. Unit of electric field N/C or V/m. Electric field at a point in space is the electric