If a 72-candela light source is located at a distance of 3 meters from a surface, the illuminance on the surface is

a. 216 lux. b. 8 lux. c. 24 lux. d. 648 lux

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?