If the power factor changes from 0.5 to 0.25 because impedance changes from Z₁ to Z₂ then Z₁ = xZ₂. The value of x is (Resistance remains constant) (a) 0.1 (b) 0.5 (c) 0.7 (d) 0.4

Answer: (b). Power factor cos φ = R/Z, so Z = (R)/(cos φ). Z₁ = R/0.5 = 2R, Z₂ = R/0.25 = 4R. Z₁ = 2R/4RZ₂ = 0.5 Z₂. So the answer is (b) 0.5.

If the power factor changes from 0.5 to 0.25 because impedance… | MHT CET 2025 (23 Apr, Shift 2)

Q21MHT CET 2025 · 23 APR · SHIFT 2Easy

Power, Power Factor & Wattless Current

If the power factor changes from 0.5 to 0.25 because impedance changes from $Z_1$ to $Z_2$ then $Z_1 = xZ_2$ . The value of x is (Resistance remains constant)

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Answer: (b)

Power factor $\cos\phi = \frac{R}{Z}$ , so $Z = \frac{R}{\cos\phi}$ .
$Z_1 = \frac{R}{0.5} = 2R$ , $Z_2 = \frac{R}{0.25} = 4R$ .
$Z_1 = \frac{2R}{4R}Z_2 = 0.5\,Z_2$ .
So the answer is (b) $0.5$ .

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