Agas of helium atoms (each of mass 6.65 × 10-27 kg) are at room temperature of 20.0°c. what is the de broglie wavelength of the helium atoms that are moving at the root-mean-square speed? (h = 6.626 × 10-34 j · s, the boltzmann constant is 1.38 × 10-23 j/k)

What happens when the vapor pressure of a liquid is equal to the external pressure?

Which statement is true about an object that is moving in a circular motion due to centripetal force, f, when the radius of its circular motion is doubled? the new force then becomes equal to 2f the new force then becomes equal to f the new force then becomes equal to f/2 the new force then becomes equal to f2 the new force then becomes equal to 1/f

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. which of the following best describes how such a telephone is able to transmit and receive information? a. the cellular telephone transmits, receives, and encodes information using only sound waves. b. the cellular telephone transmits, receives, and encodes information using only electromagnetic waves. c. the cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound. d. the cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.