An electron enters a magnetic field parallel to the field lines. Force is MCQ with Answer and Explanation

Explanation:
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:
Ampere (A) is base unit, defined via force between conductors. 1 A = 1 C/s. Coulomb is charge. Volt potential. Ohm resistance.

Explanation:
Watt (W) = Joule/second. SI unit of power. Horsepower is another unit (1 HP ≈ 746 W). Joule is energy, Newton force, Pascal pressure.