'Ringelmann scale' is used to measure density of

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UnlockIAS · Accepted Answer

Correct — A, Smoke. The Ringelmann scale (or Ringelmann chart) is a visual tool used to estimate the density, or opacity, of smoke emitted from a chimney or smokestack. Devised in the late 19th century by the French professor Maximilien Ringelmann, it is a card printed with a graduated series of shades from white through greys to black. An observer compares the darkness of the plume against the chart and reads off a number — so it is a measure of how dense/dark the smoke is, used in air-pollution monitoring.

Why the other options are wrong — (b) Water pollution is measured by parameters like BOD, COD, dissolved oxygen, pH and turbidity — not by the Ringelmann chart, which reads the darkness of an air-borne smoke plume.  (c) Fog is condensed water vapour; its extent is described by visibility range and it has nothing to do with the Ringelmann chart, which grades the blackness of combustion smoke.  (d) Noise is measured in decibels (dB) with a sound-level meter. The Ringelmann scale is purely a visual comparison of smoke shade and cannot measure sound.

Concept: The Ringelmann scale is a simple, cheap method for visually grading the opacity of smoke from a chimney. The chart runs from level 0 (all white, clear) to level 5 (all black), in steps that correspond roughly to 20% increments of blackness. A trained observer standing at a distance matches the plume against the card, giving a quick field estimate of how much particulate the source is emitting, without instruments.

State PCS 2021 Q68 — Environment & Ecology PYQ with Answer

State PCS 2021 Q68 — Environment & Ecology PYQ with Answer