Electronics Quiz 0: Understanding Kirchhoff's Laws and Basic Electronics Equations - Prof., Quizzes of Physics

Download Electronics Quiz 0: Understanding Kirchhoff's Laws and Basic Electronics Equations - Prof. and more Quizzes Physics in PDF only on Docsity! PHYS 3410 Electronics for Scientists, Dr. Sohl Quiz #0, 30 pts. total (counted towards the homework) The main purpose of this quiz is to find out what your background is. All the questions are from the introductory class text book. Do your work in the space provided, if you need more room use the back of the paper. You must show your work to get credit. Your work MUST be neat and clear and easy to read, understand and follow. Hopefully you remember Ohm’s Law and other introductory electronics equations, but just in case, here are a few: V = I R, R = ñ L / A, P = V I 1. (12 pts) This question is about Kirchoff’s laws (and thus, conservation of energy and charge). Refer to the circuits shown here. a If you start at point A in the circuit on the left and move completely around the circuit (AºBºCºDºA) ending at point A again, what is your total voltage change for the entire loop? (This is often called Kirchoff’s loop rule.) Zero, there is no voltage change if you return to the same point. b How does the current in R1 compare to the current in R2? The current is the same because the resistors are in series. c How does the current in R2 compare to the current in the battery? The current is the same because the resistors are in series. d What can you say about the current in R4 as compared to the sum of the currents in R5 and R6? (This is often called Kirchoff’s point rule.) It is equal. The sum of the current into a point is equal to the sum of the current leaving that point. 2. (6 pts) You have a flashlight circuit that is comprised of two 1.5 V batteries in series with a 6.0 Ù lightbulb. (a) How much current flows? (b) How much power is dissipated by the lightbulb? (a) I = V/R = 3.0 V / 6.0 Ù = 0.5 A (b) P = V I = 3.0 V 0.5 A = 1.5 W or P = V /R = (3.0 V) / 6.0 Ù = 9/6 W = 1.5 W2 2