Question

Ohms are a measure of resistance, amperes are a measure of current, and volts are a measure of voltage. The relationship among these three quantities is represented by the given formula. Volts Ohms Amperes A 150-ohm load is connected to a 300-volt source. If the source is changed to 250 volts, what must the resistance become to ensure that the current stays the same? A. 2 ohms B. 50 ohms C. 125 ohms D. 180 ohms E. 500 ohms

Answer 1

In order to determine what is the new resistance, first calculate the associated current for a resistance of 150-ohm and a voltage of 300-volt.

Use the following formula:

$I=\frac{V}{R}$

where:

V = 300V

R = 150Ω

replace the previous values into the formula for I:

$I=\frac{300V}{150\Omega}=2A$

Next, solve the formula for R, as follow:

$R=\frac{V}{I}$

and, in this case, use V = 250V and I = 2A:

$R=\frac{250V}{2A}=125\Omega$

Hence, the value of the new resistance must be 125 ohms