Class 9 Science Marathon - Complete - Foundation Physics

Measurement, Motion, Fluids, Electricity, Magnetism, and Light

Measurement: Definitions and Units Measurement is the process of comparing an unknown physical quantity with a known standard quantity of the same nature. The standard quantity used for comparison is called the standard unit. For example, measuring the length of a...

Which physical quantity remains constant in uniform motion?

Speed

Velocity is defined as _____ per unit time.

displacement

Direction of force acting on a current carrying conductor kept in a magnetic field is given by

Fleming’s left hand rule

The lens formula is given by

<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>1</mn><mi>f</mi></mfrac><mo>=</mo><mfrac><mn>1</mn><mi>v</mi></mfrac><mo>&minus;</mo><mfrac><mn>1</mn><mi>u</mi></mfrac></math>

What is Measurement?

Measurement is the process of comparison of a given physical quantity with a known standard quantity of the same nature. For example, measuring an unknown hand length with a known standard scale.

Differentiate between Mass and Weight.

Mass is a fundamental, scalar quantity representing the amount of matter in a body, remaining constant everywhere, and measured by a physical balance. Weight is a derived, vector quantity ($W = mg$) representing the normal force against gravitational pull, varying with location, and measured by a spring balance.