i. Prevent the backflow of mercury after use.

ii. Ensure the backflow of mercury after use.

iii. Maintain the thermometric property of mercury.

iv. Allow the temperature attained to be read.

A. i only
B. i and ii only
C. i and iv only
D. iii and iv only

Correct Answer: Option C

C. i and iv only

SEE ALSO  The diagram below illustrates an electromagnetic wave travelling with speed of 3.0 x 10^8 ms‾¹. Calculate the wavelength of the wave.

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