What is the voltage across a 10-ohm resistor if a current of 2 amperes flows through it?

The voltage across a resistor can be calculated using Ohm's Law, which states that voltage (V) equals current (I) multiplied by resistance (R). In this case, the resistor has a resistance of 10 ohms and the current flowing through it is 2 amperes.

Using the formula:

[ V = I \times R ]

Substituting the given values:

[ V = 2 , \text{amperes} \times 10 , \text{ohms} ]

[ V = 20 , \text{volts} ]

This calculation shows that the voltage across the 10-ohm resistor when a current of 2 amperes is applied is indeed 20 volts. This outcome aligns perfectly with Ohm's Law, confirming the validity of the answer.

In regard to the other choices, the calculations would yield different results that do not adhere to Ohm's Law as applied to the parameters given. Thus, they are not the correct voltage across the resistor.