B. Cosine of phase angle between voltage and current
C. Ratio of apparent power to true power
D. Ratio of resistance to impedance
Answer: Option A
Solution (By JKSSB Mock Tests)
Power factor = cosφ, where φ is phase angle between voltage and current. Also, power factor = R/Z (resistance/impedance) for series circuits, and = true power (W) / apparent power (VA). Thus both (a) and (c) are correct definitions. Memory tip: 'Power factor = cosφ = R/Z = P/S; ideal = 1 (purely resistive)'. This definition question tests AC circuit knowledge, crucial for competitive exams. Always link power factor to energy efficiency: low power factor means more current for same power, increasing losses.
Explanation:
Neutron is neutral (charge 0). Proton +e, electron -e. Alpha particle +2e. Neutron mass slightly more than proton. Discovered by Chadwick.
Explanation:
Lens maker's formula: 1/f = (μ_lens/μ_medium - 1)(...). In water, relative refractive index reduces, so power decreases, focal length increases. Glass in water behaves less converging.
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