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Physics vocabulary · Experiments and Problem Solving

Directly proportional

Meaning in physics, with examples

adjectiveCore term

In physics, directly proportional means: Describes two quantities that change at the same rate, so that if one doubles the other doubles too. Their graph is a straight line through the origin.

In Turkish: doğru orantılı

How it is used

Used constantly in explanations and exam answers: 'the extension is directly proportional to the load'. The symbol is ∝. If the straight line does not pass through the origin, examiners call it a linear relationship, not direct proportionality.

Example sentences

  1. Within the limit of proportionality, the extension of a spring is directly proportional to the force applied.

  2. The graph is a straight line through the origin, so the current is directly proportional to the voltage.

Common collocations

  • directly proportional to
  • direct proportion
  • is proportional to
  • constant of proportionality
  • inversely proportionalDescribes two quantities linked so that when one doubles, the other halves. Their product stays constant, and a graph of one against the other is a curve, not a straight line.
  • line of best fitA straight line or smooth curve drawn on a graph so that it passes as close as possible to all the plotted points, showing the overall trend of the data.
  • Ohm's lawThe rule that the current through a metal conductor is directly proportional to the voltage across it, as long as its temperature stays the same. It is usually written V = IR.
  • deriveTo obtain an equation or result step by step from basic laws or other equations, using logic and algebra instead of simply quoting it.

More terms: Experiments and Problem Solving

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