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Phys102 Q1: Term: 131 Online HW-Ch27-Lec02 A battery has an emf of 9 V and an internal resistance of 2Ω. If the potential difference across its terminals is greater than 9 V: A. B. C. D. E. it must be connected across a large external resistance it must be connected across a small external resistance the current must be out of the positive terminal the current must be out of the negative terminal the current must be zero Ans: D Q2: A 0.20 A current flows through a metallic rod of length 1.0 m when connected to a 1.0 V battery. The rod is then cut into 4 identical pieces, which are then connected in parallel to the same 1.0 V battery. The new current delivered by the battery is (Give the answer in three significant figures and SI units) Ans: 3R − 2(R + 10) = 0 3R − 2R − 20 = 0 ⇒ R = 20.0 Ω ε − 3R = 0 ⇒ ε = 3R = 60 V KFUPM-Physics Department 1 Phys102 Term: 131 Online HW-Ch27-Lec02 Q3: The current in the R 2 -resisttor in the circuit shown is: (Give the answer in three significant figures and SI units) R1 12 V R2 2R1 R3 R1 Ans: 12 V 2 R1 3 R1 E = I �2 I= R2 R2 R1 + R2� 3 E R �2 31 + R 2 � 2×6 + 4 = 8rI = 12 3 I= 12 = 1.50 A 8 KFUPM-Physics Department 2