A Certain Sample Carries a Current of 4 a When $\Omega$

question 29

Multiple Choice

A certain sample carries a current of 4 A when the potential difference is 2 V and a current of 10 A when the potential difference is 4 V. This sample:

• A) obeys Ohm's law
• B) has a resistance of 0.5 \(\Omega\) at 1 V
• C) has a resistance of 2.5 \(\Omega\) at 2 V
• D) has a resistance of 25 \(\Omega\) at 2 V
• E) does not have a resistance

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Definitions:

Existential Generalization

A logical inference rule stating that if an assertion is true for some member of a domain, then there exists an element in that domain for which the assertion holds.

Universal Generalization

A logical principle stating that what is true of all instances of a certain class can be said to be generally true of that class.

Existential Instantiation

A logical principle allowing for the inference of the existence of an instance of a predicate from a statement asserting the existence of some (possibly unspecified) instance.

Universal Instantiation

A logical rule stating that if something is true for everything in a certain category, it is true for each specific member of that category.