A helicopter has blades of length 4.0 m rotating at 3.0 rev/s in a horizontal plane. If the vertical component of the Earth’s magnetic field is 6.5 105T, what is the induced emf between the tip of a blade and the hub?

Afixed electric space heater wired by a cable with an ampacity of 30 a should draw a maximum current of a. 30 a. b. 24 a. c. 15 a. d. 27 a.

What is the energy of a photon of ultraviolet radiation with a frequency of 4.4 × 1015 hz? planck’s constant is 6.63 × 10–34

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.