Question

why the level of mercury should change at all when the bulb of the thermometer is brought in an contact with another object???​

Answer 1

Answer:

it is converted into liquid form that's why the Mercury should change at the bulb of the thermometer your walcome

Answer 2

Answer:

Because the mercury in the bulb changes temperature by absorbing or releasing heat. Mercury, like most substances, has a positive thermal expansion coefficient, so the mercury expands as its temperature goes up (or contracts if it’s temperature drops). Since the volume of the bulb remains (mostly) constant, the liquid mercury flows into or out of the only direction it can: the narrow path above the bulb

Explanation:

hope this will help you