Which is a tool used by scientists to determine the composition of objects?

A. a hologram

B. a spectrometer

C. a wave front

D. a prism

A beam of yellow light is made to pass through two slits that are 3.0 x 10-3 meters apart. On a screen 2.0 meters away from the slits, an interference pattern appears with bands of light separated by 3.9 x 10-4 meters.

Ian walks 2 km to his best friend's house, then walks 0.5 km to the library. He then makes a 2.5 km walk home. The entire walk took him 3 hours. What is his average speed in km/h? SHOW YOUR WORK!

A 60-g sample of radioactive isotope is measured after two half-lives have passed. What pair of percentages describes the sample after two half-lives? 50% unchanged and 50% stable 25% unchanged and 75% stable 12.5% unchanged and 87.

Which dinosaur had teeth that measured six inches

What is the speed of a wave with 3Hz frequency and a wavelength of 9 m

When a fork is placed in a hot piece of lasagna, thermal energy is transferred up the fork by ...

Levi observed properties of four different waves and recorded observations about each one in his chart.

A rocket is shot straight up from the earth, with a net acceleration (acceleration by the rocket engine minus gravitational pullback) of during the initial stage of flight until the engine cut out at sec.

Which moon has a thick atmosphere made mostly of nitrogen?

J. J Thompson proposed that atoms were made up of positively charged particles with electrons scattered into them. How did he reach this conclusion?