Mastering Physics: Resistance and Geometry

Mastering Physics: Resistance and Geometry

Part A

Question: Which conductor in the table has the greatest resistance?

Answer: E

Part B

Question: Which conductor in the table has the greatest resistivity?

Answer: There is not enough information given.

Part C

Question: Which conductor in the table has the lowest resistance?

Answer: D

Part D

Question: Which conductor in the table has the greatest cross-sectional area?

Answer: There is not enough information given.

Part E

Question: Which conductor in the table obeys Ohm's law?

Answer: There is not enough information given.

Part F

Question: Which conductor has a resistance of 5 ohms?

Answer: C

Part G

Question: Assuming that all conductors obey Ohm's law, which conductor would carry a current of 12 amperes when the voltage across it was 30 volts?

Answer: B

Part H

Question: What is the current I across conductor C when the voltage across it is 10 volts? Assume that the conductor obeys Ohm's law.

Answer: 

R = V / I

R = 100 / 20

R = 5 Ω

I = V / R

I = 10 / 5

I =  2.0  A

Part I

Question: If the current through conductor D is 10 amperes, what is the voltage V across it? Assume that the conductor obeys Ohm's law.

Answer: 

R = V / I

R = 20 / 100

R = 0.2 Ω

V = I × R

V = 10 × 0.2

V =  2.0  V