Question

Calculate least count of the voltmeter if there are 10 divisions between 0V and 0.5 V.

Answer 1

Hint: The voltmeter is the device that is used to measure the potential difference across the conductor. The voltmeter is always connected in parallel with the circuit.

Complete step by step answer:
Least count of the apparatus is defined as the smallest measurement by the apparatus. The least count of the measuring scale is 0.1 cm. So, the least distance measured by the scale is 0.1 cm. The zero-error division is multiplied by the least count. This value is then added or subtracted to the final reading of the apparatus.
The accuracy in the measurement increases if the least count of the apparatus is minimum. The length of the rectangular block can be measured using the micrometre screw gauge and the Vernier calliper. The least count of the micrometre is 0.001. The least count of the Vernier calliper is 0.01. So, the micrometre screw gauge is used for better calculations.
Given:
Lowest value of voltmeter, V = 0V
Highest value of voltmeter, V’= 0.5V
Number of divisions, n = 10
Calculation:
The range of the voltmeter is given as:
Range= Highest value – lowest value
Range = 0.5 V- 0 V
Range = 0.5 V
The least count of the apparatus is the fraction of the range of the voltmeter and the number of divisions.
$\begin{array}{rl}& \Rightarrow \text{Least}\text{count=}{\displaystyle \frac{\text{Range}}{\text{Number}\text{of}\text{division}}}\\ & \Rightarrow \text{Least}\text{count=}{\displaystyle \frac{\text{0}\text{.5}}{\text{10}}}\\ & \Rightarrow \text{Least}\text{count=0}\text{.05}\end{array}$

Note:
Another method for calculation of the least count:
$\begin{array}{rl}& \Rightarrow \text{Least}\text{count=}{\displaystyle \frac{\text{Value}\text{measured}\text{in}\text{n}\text{division}}{\text{Number}\text{of}\text{division}}}\\ & \Rightarrow \text{Least}\text{count=}{\displaystyle \frac{\text{0}\text{.5}}{\text{10}}}\\ & \Rightarrow \text{Least}\text{count=0}\text{.05}\end{array}$