The instrument commonly used to demonstrate the knee-jerk reflex is called a reflex hammer. It is a small, handheld device typically made of rubber and metal, designed to strike tendons gently to elicit reflex responses. The most common reflex tested is the patellar reflex, which involves the knee-jerk response when the patellar tendon is tapped.
Rheostat is the name of an instrument used to vary electrical resistance.
syringe
Timepieces.
a compass i think
Bongos.
A set square !
Telescope.
Electronic microscope
The instrument used to measure the volumes of liquids are many as follows ..they are : beaker ,burette,pipette,etc.
The name is an aspergillum.
A contraction
barometer