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:
Sir C. V. Raman discovered the Raman effect in 1928: inelastic scattering of photons by molecules, changing wavelength, providing information about molecular structure. He received the Nobel Prize in Physics in 1930. Photoelectric effect: Einstein; relativity: Einstein; electromagnetic induction: Faraday. Memory tip: 'Raman = scattering of light'. This scientist-discovery question tests knowledge of Indian contributions to physics, commonly featured in competitive exams. Always link Nobel laureates to their specific awarded work.
Explanation:
Water has a specific heat capacity of 4184 J/kg·K, which is very high. This means it heats up and cools down much more slowly than land. During the day, land heats faster than the sea, causing air above it to rise and cool air from the sea to rush in (sea breeze). The reverse happens at night (land breeze).
No comments yet. Be the first to start the discussion!