Q. A dolphin located in sea water at a temperature of 25°C emits a sound directed toward the bottom of the ocean 481 m below. How much time passes before it hears an echo? The speed of sound in sea water is 1530 m/s.
Q. A parallel-plate air-filled capacitor having area 44.0 cm2 and plate spacing 2.80 mm is charged to a potential difference of 620. V. Find
(a) the capacitance (b) the magnitude of the charge on each plate