Physical Quantities & Measurement: Class 9 Physics Worksheet

Length, mass and time are base quantities with SI units of the metre, kilogram and second. Accurate measurement depends on the right tool: a screw gauge for the diameter of a thin wire, vernier callipers for small lengths and diameters, and a measuring cylinder for the volume of a liquid. Class 9 students answer 15 marks of four-option MCQs on units and instruments.