Deck 7: Ohms Law of Constant Proportionality

Question 1

Which of the following statement most accurately describes Ohm's Law?

A) The current flowing through a conductor is proportional to the voltage across that conductor
B) The current flowing through a conductor is equal to the voltage across that conductor, divided by its resistance
C) The ratio of voltage to current is constant for variations in voltage

Answer 1

The ratio of voltage to current is constant for variations in voltage

Question 2

Not all materials or devices obey Ohm's Law. Those that do, are termed

A) linear or ohmic
B) non-linear or non-ohmic
C) insulators
D) electrolytes

Answer 2

linear or ohmic

Question 3

For those materials or devices that obey Ohm's Law, a graph of their voltage against current results in a

A) straight-line graph
B) non-linear graph

Answer 3

straight-line graph

Question 4

The ratio of voltage to current represents the __________ of a material or device, regardless of whether or not it obeys Ohm's Law

A) conductance
B) resistance
C) resistivity

Question 5

When a voltage of 12 V is applied across a resistance of 10 ohms, a current of 1.2 A results. Does this resistance obey Ohm's Law?

A) yes
B) no
C) there is not enough information to tell

Question 6

When a voltage of 200 V is applied across a circuit, the resulting current is 5 A. When the voltage is increased to 300 V, the resulting current is 7.5A. Does the circuit probably obey Ohm's Law?

A) Yes, because the ratio of voltage to current remains constant for a change in voltage
B) No, because a change in voltage results in a different value of current

Question 7

Does a tungsten lamp filament obey Ohm's Law?

A) Yes, because it is a pure metal conductor
B) No, because its resistance increases significantly as the voltage applied across it increases

Question 8

When a voltage of 15 V is applied to a resistance of 3 ohms, the resulting current is

A) 0.333 A
B) 5 A
C) 45 A

Question 9

When a voltage of 200 V results in a current of 2.5 A, the resistance of circuit is

A) 500 ohms
B) 80 ohms
C) 12.5 milliohms

Question 10

When a current of 3 A passes through a resistance of 75 ohms, the voltage across that resistance must be

A) 0.04 V
B) 25 ohms
C) 225 ohms