Correct Answer - Option 2 : ± 0.3°C
Concept:
Absolute Error: The deviation of the measured value from the true value (or) actual value is called error. It is also known as a
static error.
Static error (E) = Am – At
Am = Measured value
At = True value
It is caused due to measuring device.
Span: It is defined as the difference between the largest and smallest reading of the instrument.
Calculation:
A thermometer is calibrated from 150°C to 300°C
Maximum value = 300°C
Minimum value = 150°C
Span = 300 - 150 = 150°C
Static error = ± 0.2% of span
= ± 0.2% of 150
= ± 0.3°C
Relative Static Error: The ratio of absolute error to the true value is called relative static error.
\(R.S.E = \frac{{\left| {{A_m} - {A_t}} \right|}}{{{A_t}}} \times 100\)
Limiting Error:
The maximum allowable error in the measurement is specified in terms of true value, is known as limiting error. It will give a range of errors. It is always with respect to true value, so it is a variable error.
Guaranteed Accuracy Error:
The allowable error in measurement is specified in terms of full-scale value is known as a guaranteed accuracy error. It is a variable error seen by the instrument since it is with respect to full-scale value.
