1. A. The SI unit for current is the ampere. 2. C. The unit for resistance = ohm. 3. B. EMF is measured in volts. 4. B. Electric current is the flow of charged particles, i.e. electrons. 5. B or C. All other answers are metals. 6. C. The dimensions of a material don't affect its resistance. 7. D. Ohm's law: current = voltage / resistance, 12/4 = 3. 8. B. Batteries transform chemical energy into electrical energy. 9. A. Metals are generally good conductors.
As the metal expands as does the road bed so neither really effevts those foing over the bridge. as it is hot the metal will expand and so will most tarmac on roads.