Write your answers on your own paper with your name and the version number of this assessment at the top. Each question is worth 3 points unless stated otherwise. B₁ B2 B2 • Elementary charge: 1.6 x 10-19 C k = = 1 Απερ = 9.0 × 109 N m² B₁ B₁ 2 2 B3 B2 B3 B3 3 4 Figure 1 3 Figure 2 3 Figure 3 1. Choosing from figures 1, 2, and 3 above, in which case will bulb B₁ be the dimmest if all the bulbs and batteries in all the circuits are identical? 2. Focusing on Figure 2, if all the bulbs are identical, how does V12, the potential difference between points 1 and 2, compare to V23, the potential difference between points 2 and 3? a) V12 < V23 V23 b) V12 > Vol bourgi ai c) V12 = V23 4. 3. Assuming an ideal battery and that all the bulbs and batteries in all the circuits are identical, in which of the circuits above does the battery supply the greatest current? In the circuit to the right, the bat- tery is 12 V, R₁ = 60, R2 = 120, and R3 = 80. Find the voltage drop across each resistor, the current through each resistor, and the power provided by the battery to run the circuit. R₁ R2 In R3 5. What would the cross-sectional area need to be for copper wire (conductivity = 5.9 x 107 (2m)-1) in order to create a 1002 resistor using a 100 m length of wire? 6. In class we discussed a "knight and barn" problem where the knight held a 20 m long lance and the barn was 12 m long. We found that the lance would momentarily fit inside the barn if the speed of the knight was ẞ= 0.8. boldal (a) Show that length contraction does indeed predict that the lance will be measured to be 12 m long by observers at rest relative to the barn. (b) Determine the length of the barn as measured by the knight. al (s) bid 1A (d)