Question 1
Most telephone cables are made of copper wire of either 24 or 26 gauge. If the resistance of 24-gauge wire is 137 Ω/mile and the resistance of 26-gauge wire is 220 Ω/mile, what is the ratio of the diameter of 24-gauge wire to that of 26-gauge wire?
◦
1.6
◦
1.3
◦
0.62
◦
0.79
◦
0.88
Question 2
The electron density in copper is 8.49 × 1028 electrons/m3. The electron charge is e = −1.60 × 10−19 C. When a 1.00 A current is present in a copper wire with a 0.40 cm2 cross-section, the electron drift velocity, in m/s, with direction defined relative to the current density, is
◦
−1.84 × 10−6.
◦
+1.84 × 10−6.
◦
−1.84.
◦
−5.43 × 105.
◦
+5.43 × 105.
Electron Transport Chain
electron microscope image of a diatom
Insects Under the Electron Microscope
copper
Physics - Density and Pressure