advertisement

Exam 1, PHYS 202 Chapters 25, 26, 27, & 28 8 March 2006 Name________________________ 1) In this figure, the resistances are R1=3.0 Ω and R2=1.0 Ω, and the ideal batteries have emfs E1=1.0 V and E2=5.0 V. What are a) size and direction (up or down) of current in battery 1______________ b) size and direction of current in battery 2 ______________ c) size and direction of current in battery 3 ______________ d) the potential difference Va-Vb ______________ 2) In this figure, how much charge is stored on the parallel-plate capacitors by the 10 V battery? On is filled with air, and the other is filled with a dielectric for which κ=2.00; both capacitors have a plate area of 2.50x10-3 m2 and a plate separation of 3.00 mm. Q1=_____________ C Q2=_____________ C 3) A 120 V potential difference is applied to a space heater whose resistance is 20 Ω when hot. a) At what rate is electrical energy transferred to thermal energy? ________ b) What is the cost for 6 hours at US$0.05/kW·h? ________ 4) An electron has an initial velocity of (10000 ˆj + 13000kˆ)m / s and a constant acceleration of (3.00 × 1012 m / s 2 )iˆ in a region in which uniform electric and magnetic fields are present. If B = (400 µT )iˆ , find the electric field E . 5) In this figure, R1=200 Ω, R2=100 Ω, R3=100 Ω, R4=150 Ω, and the ideal battery has emf E=5.00 V. a) What is the equivalent resistance? ___________ b) What is the current in resistance 1?___________ c) What is the current in resistance 2?___________ d) What is the current in resistance 3?___________ e) What is the current in resistance 4?___________