Question

What is a Chronometer?
A. It is a clock for determining the longitude of a vessel at sea.
B. It is an instrument for changing or reversing the direction of electric current.
C. It is an instrument for measuring the direction and velocity of wind.
D. It is an instrument for comparing intensities of colours.

Answer 1

Hint: We know that the name by itself suggests that the device could be something related to time. Yes, you are right, a chronometer indeed is a timepiece. However, it has certain characteristic properties that make it possible to do one among given functions. You could thus identify the correct option.

Complete step by step answer:
In the question, we are asked what chronometer is.
It basically is a clock. They are very precise and accurate that they can be used as a portable time standard. It could make these accurate measurements in spite of the variations present in humidity, air pressure and even temperature. Hence it can be used as a clock for determining the longitude of a vessel at sea.

So, the correct answer is “Option A”.

Additional Information: The official Swiss chronometer testing institute (COSC) has to certify the timepieces to be chronometers. We have to rate a chronometer before it is put into work. By that we mean that average rate of gain or loss per day observed, noted and certified. This daily rate is then used to correct the reading indicated by the instrument.

Note: Even the very best chronometers are known to show two types of errors, namely, random and consistent. These errors cannot be completely and hence we use the method of rating to make accurate measurements. However, the rate of a chronometer also changes overtime due to the thickening of oil and hence the rate should be periodically checked on long expeditions.