Physics II Do Not Write on This Question Sheet! Lab Quiz Prelab Quiz - Ohm's Law 26. What is the name of a device designed to measure a potential difference? (A) Ammeter (B) Galvanometer (C) Ohmmeter (D) Voltmeter (E) Thermometer 27. In Figure 1, the ammeter reads 0.8A and the voltmeter reads 5.6V. What is the resistance R? (A) 4.5 V (B) 4.5 (C) 7.0 (D) 0.14 £2 (E) 7.0 V A R Figure 1: Simple Electric Circuit 28. An aluminum wire of a diameter of 5mm is 10.0m long. Calculate the resistance of this wire. Resistivity of aluminum is 2.82e-8 m. (Α) 4.51 ΠΩ (B) 45.1e-32 (C) 14.4 m2 (D) 1.12e-3 m2 (E) 5.64e-5 m 29. If a potential difference across the ends of a wire will be doubled in magnitude and the length of the wire will be cut in a half at the same time, how will it change the current passing through the wire? (A) There will be no change in the current passing through the wire. (B) The current passing through the wire will be doubled. (C) The current passing through the wire will be halved. (D) The current passing through the wire will be quadrupled. (E) There will be 4x drop in the current passing through the wire. 30. When human skin is wet, the overall resistance of a human body drops down to 1k. If a person covered in sweat after a workout accidentally touches 120V outlet, what would be the current passing through the body? (A) 120 A (B) 8.3 A (C) 0.12 A (D) 12.0 A (E) 8.3 mA