Tag: science & technology

Henry is the SI unit of inductance, representing the ratio of voltage to rate of change of current in an inductor. One henry produces one volt when current changes at one ampere per second.

Gauss is the CGS unit of magnetic flux density (B field), also commonly called magnetic field in everyday usage. Magnetic field intensity (H) is measured in different units (A/m in SI). The key distinction is that flux density describes the force field's strength, while intensity describes the external field's cause.

Kelvin is the SI base unit for thermodynamic temperature, which is the absolute temperature scale starting from absolute zero. 'Temperature' alone could refer to Celsius or Fahrenheit scales, but thermodynamic temperature specifically refers to the absolute Kelvin scale.

Watt is the SI unit of power, which is the rate of doing work or transferring energy (joules per second). Energy itself is measured in joules, force in newtons, and work is also measured in joules. Power is distinct because it measures how fast energy is used or transferred.

Shot peening is a cold working process that bombards a surface with small spherical media to induce compressive residual stresses. These compressive stresses counteract tensile stresses during service, significantly delaying fatigue crack initiation and propagation in welds and springs. The other options (normalizing, spheroidizing, martempering) are heat treatments that primarily alter microstructure, not surface stress state.

Ohm is the SI unit of electrical resistance, which opposes current flow in a circuit. Conductance is the reciprocal of resistance (measured in siemens), inductance opposes changes in current (measured in henry), and capacitance stores charge (measured in farad).

Siemens is the SI unit of electrical conductance, which is the measure of how easily electric current flows through a material. It is the reciprocal of resistance (ohm). Inductance is measured in henry, capacitance in farad, and resistance in ohm.

Lux is the SI unit of illuminance, which measures luminous flux (light power perceived by human eye) per unit area. It is distinct from luminous intensity (candela) or luminous flux (lumen). Illuminance describes how much light falls on a surface.

Curie is a unit of radioactivity (specifically, activity of radioactive sources), measuring the number of nuclear decays per second. It quantifies how radioactive a substance is, not bond strength, reaction rates, or isotope counting.