Prepare for the MTA Transit Electrical Helper Exam with flashcards and multiple-choice questions. Hints and explanations accompany each question. Get ready for your exam!

Multiple Choice

Which instrument is used to accurately measure the resistance of a 4700 ohm resistor?

The instrument used to accurately measure the resistance of a 4700 ohm resistor is an ohmmeter. This device is specifically designed for measuring electrical resistance in components such as resistors. When an ohmmeter is connected across a resistor, it applies a small voltage and measures the resulting current flow to calculate the resistance using Ohm's Law (R = V/I). This method allows for precise readings of resistance values in the ohm range, including 4700 ohms, which is a standard resistor value. While other instruments, like a voltmeter or an ammeter, measure voltage and current respectively, they are not equipped to directly measure resistance. A megger, typically used for measuring insulation resistance in high-voltage applications, operates on a different principle and is not intended for standard resistor measurements. Hence, the ohmmeter is the appropriate choice for this purpose.

The instrument used to accurately measure the resistance of a 4700 ohm resistor is an ohmmeter. This device is specifically designed for measuring electrical resistance in components such as resistors.

When an ohmmeter is connected across a resistor, it applies a small voltage and measures the resulting current flow to calculate the resistance using Ohm's Law (R = V/I). This method allows for precise readings of resistance values in the ohm range, including 4700 ohms, which is a standard resistor value.

While other instruments, like a voltmeter or an ammeter, measure voltage and current respectively, they are not equipped to directly measure resistance. A megger, typically used for measuring insulation resistance in high-voltage applications, operates on a different principle and is not intended for standard resistor measurements. Hence, the ohmmeter is the appropriate choice for this purpose.