The scientist who discovered the link between electricity and magnetism was MCQ with Answer and Explanation

Explanation:
Kepler's Third Law (Law of Periods) states that the square of the time period (T^2) of any planet is proportional to the cube of the semi-major axis (r^3) of its orbit. Mathematically, T^2 is proportional to r^3. This law helps in calculating orbital periods or distances of planets and satellites.

Explanation:
Time period T = 1/f = 1/200 = 0.005 s = 5 ms. Frequency is number of cycles per second. Relationship T = 1/f is fundamental. For 200 Hz, period is 5 milliseconds.

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.