An ultrasound wave has frequency 2 MHz. Time period is MCQ with Answer and Explanation

Explanation:
RMS value of AC is defined such that I_rms²R = average power dissipated, same as DC current I_dc would produce (I_dc²R). Thus I_rms = I₀/√2 for sinusoidal AC. This definition ensures power calculations use RMS values. Memory tip: 'RMS: heating effect equivalent to DC; I_rms = 0.707 I₀ for sine wave'. This AC fundamentals concept is frequently tested in competitive exams. Always use RMS values for power calculations in AC circuits; peak values overestimate power.

Explanation:
Standard atmospheric pressure 1 atm = 1.01325 × 10⁵ Pa ≈ 1.01 × 10⁵ Pa = 101 kPa. Also equals 760 mm of Hg. This is an important conversion for pressure units.

Explanation:
v = √(gR) = √(10×6400×10³) = √(64×10⁶) = 8×10³ m/s = 8 km/s. Escape velocity 11.2 km/s.