B5 solutions: Resistance
1. At 0°C a steel cable is 1km long and 1cm diameter when it is heated it expands and its resistivity increases. Calculate the change in resistance of the cable as it is heated from 0 - 20°C The temperature coefficient of resistance αr gives the fractional increase in resistance per °C.So increase in resistance ΔR = RoαrΔTWhere Ro is the resistance at 0°CFor steel αr = 0.003 °C-1 The coefficient of linear expansion...