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COMEDK2023Evening ShiftPhysicsUnits and DimensionsActual

The time dependence of a physical quantity P is give by P=P ₀ (- t^2 ) where is a constant and t is time. The constant will

Options

  1. AHave no dimensions
  2. BHave dimensions as that of P
  3. CHave dimensions equal to that of Pt ^2
  4. DHave dimensions of t⁻²

Correct answer

D. Have dimensions of t⁻²

Step-by-step solution

The given equation is P = P₀ (- t^2) . In any exponential function of the form e^x , the exponent x must be dimensionless. Therefore, the term t^2 must be dimensionless. [ t^2] = [M^0 L^0 T^0] = 1 . Since t represents time, its dimension is [T] . Thus, [ ] [T^2] = 1 . [ ] = [T⁻²] . This implies that the constant has dimensions of t⁻² . Answer: Have dimensions of t⁻²

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