Homework #5HW ProblemsHomework #5 Physics 11b Morii 3/10/2005 Due 3/18/2005, 4 PM in mailboxes outside Science Center 109 Read: Chapters 29, 30 Instructions: Please box your solutions. The homework problems are graded out of 3 points, and then the total re-scaled to 30. For each problem, in order to get full credit, you must also include a sentence explaining the most important idea you used in order to solve it. Do not summarize the whole solution, simply the one most important idea. HW Problems 1. Serway & Jewett 28.4 An automobile battery has an emf of 12.6 V and an internal resistance of 0.0800 Ω. The headlights together present equivalent resistance 5.00 Ω (assumed constant). What is the potential difference across the headlight bulbs (a) when they are the only load on the battery and (b) when the starter motor is operated, taking an additional 35.0 A from the battery? 2. Serway & Jewett 28.6 (a) Find the equivalent resistance between points a and b in the figure below. (b) A potential difference of 34.0 V is applied between points a and b. Calculate the current in each resistor.3. Serway & Jewett 28.14 A 6.00-V battery supplies current to the circuit shown in the figure below. When the double-throw switch S is open, as shown in the figure, the current in the battery is 1.00 mA. When the switch is closed in position 1, the current in the battery is 1.20 mA. When the switch is closed in position 2, the current in the battery is 2.00 mA. Find the resistances R1, R2, and R3. 4. Serway & Jewett 28.24 Using Kirchhoff’s rules, (a) find the current in each resistor in the figure below. (b) Find the potential difference between points c and f. Which point is at the higher potential?5. Serway & Jewett 28.28 For the network shown in the figure below, show that the resistance Rab = (27/17) Ω. 6. Serway & Jewett 28.36 In the circuit of the figure below, the switch S has been open for a long time. It is then suddenly closed. Determine the time constant (a) before the switch is closed and (b) after the switch is closed. (c) Let the switch be closed at t = 0. Determine the current in the switch as a function of time. 7. Serway & Jewett 29.4 A proton travels with a speed of 3.00 × 106 m/s at an angle of 37.0° with the direction of a magnetic field of 0.300 T in the +y direction. What are (a) the magnitude of the magnetic force on the proton and (b) its acceleration?8. Serway & Jewett 29.14 A conductor suspended by two flexible wires as shown in the figure below has a mass per unit length of 0.040 0 kg/m. What current must exist in the conductor in order for the tension in the supporting wires to be zero when the magnetic field is 3.60 T into the page? What is the required direction for the current? 9. Serway & Jewett 29.32 A proton moving freely in a circular path perpendicular to a constant magnetic field takes 1.00 µs to complete one revolution. Determine the magnitude of the magnetic field. 10. Serway & Jewett 29.36 A singly charged ion of mass m is accelerated from rest by a potential difference ∆V. It is then deflected by a uniform magnetic field (perpendicular to the ion’s velocity) into a semicircle of radius R. Now a doubly charged ion of mass m’ is accelerated through the same potential difference and deflected by the same magnetic field into a semicircle of radius R’ = 2R. What is the ratio of the masses of the