Question

function of kink in a clinical thermometerfunction of k*** in a clinical thermometer

Answer 1

When the thermometer's in the patient's mouth (or wherever), it expands up to the temperature of the patient. 
As it's pulled out, it starts to cool and contract back into the bulb. 
The kink is designed to 'break' the thread of the mercury (or alcohol), so the part closest to the bulb contracts back into the bulb, while the remaining section of mercury just contracts where it is in the tube. 
This means that the temperature read off the scale is a lot more accurate. 
Without the kink, more liquid would contract back to the bulb, leading to consistently low readings. 

Answer 2

Function of kink in a clinical thermometer is
 A 'kink' in the glass tube which breaks the mercury as it contracts, storing the highest temperature reading. it is mostly used by the doctors for checking the body temperature.