Hint: An oscilloscope is a device which is used to measure or analyse the change in voltage over a period of time. While a voltmeter is used to measure the potential difference between two points. An ideal voltmeter has infinite resistance. Oscilloscopes are mainly of two types and both have different functions. The Cr oscilloscope converts all data to voltage while the Dr oscilloscope converts to digital signals.
Complete step-by-step solution:
Oscilloscope is an instrument which is used to measure voltage signals over a time period. Oscilloscopes are used to monitor the electric signals over a period of time.
A device used to measure potential between two points in a circuit is called voltmeter.
There are different types of oscilloscopes and one of them is the cathode ray oscilloscope. The CR oscilloscope mainly functions on voltages. Therefore, we can use a CR oscilloscope to measure the potential difference between two points and also observe how it varies over time but these are not readily available now-a-days.
CR oscilloscopes are good voltmeters because they have almost infinite resistance so it is very close to an ideal voltmeter.
Therefore, a cathode ray oscilloscope can be used as a voltmeter.
Note: Current flows due to the potential difference between two points as current flows from a region of higher potential to a region of lower potential. The most common types of oscilloscopes are the digital storage oscilloscopes as it is easier to use and more convenient. CR oscilloscope converts current, acceleration, frequency etc into voltage while the DS oscilloscope stores everything as digital signals.