ured length.  Measurement errors are another type of uncertainty involved in single measurements. Suppose we measure the diameter of a disk. The minimum length that can be measured on the stick is 1 mm (0.1 cm). If the diameter lies somewhere between 5.1 cm and 5.2 cm, which value do we report? In such cases the value is reported as 5.15 ± 0.05 cm. Note that the uncertainty of the measurement is one half the smallest tick mark on the measuring device. This applies to all instruments. A sound experimental procedure involves several measurements of the physical quantities required in one of several ways. Once those measurements have been made, we compute the statistical quantities listed in the key concepts above to make inferences from the data obtained. Question 1 (write down answers on Report Sheets) Below are three sets of measurements of the boiling point of water at 1 standard atmosphere (atm): Measurement 1 2 3 4 5 Set A 99.8 °C 99.8 °C 99.8 °C 99.8 °C 99.8 °C Set B 100.0

  T = (99.78 ±0.05) ºC

Explanation:

This problem refers to the procedure to perform the measurements and their correct reporting.

Suppose that the thermometer used has an appreciation of 0.1ºC and the values of 5 measurements resulted in

 #     T (ºC)

 1      99.8

 2     99.7

 3     99.7

 4     99.8

 5     99.9

the processing calculate mean value

   T_average = ∑ / n

   T_average = (99.8 + 99.7 + 99.7 + 99.8 + 99.9) / 5

   T_average = 99.78ºC

the absolute error or uncertainty of the measurement is half the appreciation of the instrument

       ΔT = ± 0.05ºC

so the result must be written

        T = (99.78 ±0.05) ºC

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explanation:

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia