Question

The diagram shows liquid in a burette and in a measuring cylinder. Which row shows the readings for the burette and the measuring cylinder?

(A) Burette- 27.8, Measuring cylinder- 42
(B) Burette- 27.8, Measuring cylinder- 44
(C) Burette- 28.2, Measuring cylinder- 42
(D) Burette- 28.2, Measuring cylinder- 44

Answer 1

Hint- In order to solve the given problem and find the reading or the measurement of each of the measuring instruments, first we will understand the concept of measurement and scale reading. In order to find the reading of the burette and the measuring cylinder, first we will look for major reading and further we will look for intermediate or fractional or decimal reading on the basis of least count of the instruments.
Complete answer:
> The instruments given above have two different types of scale. Burette has a downward scale where the minimum reading is at the top and the maximum reading is at the bottom. > But in the case of the measuring cylinder the condition is reversed, the minimum reading is at the bottom and the maximum reading is at the top.
For reading of the scale and understanding the measurement of the scale the skill needed is called scale reading.
> Scale interpretation is an essential skill in numeracy. This also deals with ideas surrounding number line length. Students require a good knowledge of decimal symbols to allow measurements in between marked points on a scale.
> In the scale there are two types of marks normally one is the primary or the main mark which has a bold or dark marking with some numerical value written along and the other is the secondary or small marking which are smaller in size or less dark. These small marks are provided on the basis of the least count of the scale of the instruments. Each space between the small marks measures the same as the least count of the scale.
> Least count of the scale can be referred to as the minimum quantity the scale can measure.
> Now, on the basis of the above understanding we will find out the reading of each of the instruments.
In the first scale the major marks are 27, 28, and 29.
And there are 10 minimum divisions between each of the major divisions.
So, the least count of the burette is:
$\Rightarrow {\text{Least count}} = \dfrac{{{\text{Difference between major division}}}}{{{\text{Number of division}}}} \\
   = \dfrac{{28 - 27}}{{10}} \\
   = \dfrac{1}{{10}} = 0.1 \\ $
Now as the mark is between 27 and 28 so the major reading will be 27.
Also we can see that the mark is at the 8th division after 27. So the minor reading will be:
$ = 8 \times 0.1 \\
   = 0.8 \\ $
 Hence, the overall reading of the burette is:
$= 27 + 0.8 \\
   = 27.8 \\ $
Similarly let us see for the measuring cylinder.
In the first scale of the measuring cylinder major marks are 10, 20, and 30.
And there are 5 minimum divisions between each of the major divisions.
So, the least count of the measuring cylinder is:
$\Rightarrow {\text{Least count}} = \dfrac{{{\text{Difference between major division}}}}{{{\text{Number of division}}}} \\
   = \dfrac{{20 - 10}}{5} \\
   = \dfrac{{10}}{5} = 2 \\ $
Now as the mark in the measuring cylinder is between 40 and 50 so the major reading will be 40.
Also we can see that the mark is at the 2nd division after 40. So the minor reading will be:
$ = 2 \times 2 \\
   = 4 \\ $ Hence, the overall reading of the measuring cylinder is:
$ = 40 + 4 \\
= 44 \\ $
Hence, the readings for the burette and the measuring cylinder are Burette- 27.8, Measuring cylinder- 44.So, the correct answer is option B.

Note- In order to solve such a type of problem students must be aware of the concept of least count of the instrument and must remember the method to calculate the least count of any instrument. A measuring device scale comprises the markings indicating a certain amount of what is being measured. The number of marks on a measuring device relays just how accurate a measurement can be. Burette is a laboratory instrument used to measure the amount of a liquid or a gas in quantitative chemical analysis. A measuring cylinder or mixing cylinder is also a commonly used laboratory device which is generally used to measure a liquid's volume and has similar function as the burette.