The graph shows the characteristics of a sound wave in air. The wave is traveling at 344 meters per second. What is the frequency of the wave?
|A)||about 53 cycles per second|
|B)||There is not enough information to solve this problem.|
|C)||2,064 cycles per second|
|D)||0.017 cycles per second|
|E)||43 cycles per second|
CDs and DVDs are examples of optical storage. Both kinds of disks store information using a spiral of microscopic pits. The pits hold a digital code that can be read by a laser. (A laser is an intense light source of a single wavelength of light. The light travels with its wave crests and troughs aligned.) DVDs can hold more than four times as much information as CDs because the pits used to store the information are much smaller on DVDs than on CDs. The smaller pits on DVDs can be read with a laser with shorter wavelength.
Which of the following blends opinion and fact?
|A)||Reducing pit size means that the pits can be closer together. If the pits are closer together, the spirals can be closer together too.|
|B)||Information held in smaller pits in the DVD can be read with lasers having different frequencies of light.|
|C)||CDs require infrared light to be read, but DVDs require red light. If pits are made even smaller, it will be possible to read them with either blue or green lasers.|
|D)||If pits are made even smaller than those on DVDs, the information could be read with lasers of even shorter wavelength.|
|E)||DVDs are better than CDs because they store more information.|
The advertising for a string of holiday lights claims, "When one burns out the others stay lit—guaranteed." Which is the most reasonable conclusion you can draw from the advertisement?
|A)||The lights are wired in parallel.|
|B)||They have the Underwriter’s Laboratory (UL) seal of approval.|
|C)||Each light bulb is designed so electricity can flow through it even when it is burned out.|
|D)||The wires in the string of lights will become warmer after one bulb burns out.|
|E)||The lights are in a series circuit.|
Unlike bar and horseshoe magnets these round refrigerator magnets have no ends to label either N or S. Anika wondered if they even had N and S poles.
The illustration shows some observations Anika made with the magnets. In illustration A, the magnets are close together but not attracted to one another. In B, one of the magnets has been turned 180°; the magnets are still not attracted to one another. In C, one magnet floats in air above the other, and in D the magnets attract one another. Which statement about the refrigerator magnets is a conclusion you can reach using the illustrations?
|A)||Disc-shaped magnets have no poles.|
|B)||C and D together show that the poles of the magnets are above and below the plane of the disk.|
|C)||D shows the magnets with their like poles together.|
|D)||Together, A and B show that the poles of the magnets are along their edges.|
|E)||B shows that the pole of each disk magnet is in the center of each disk.|
When the temperature of a gas increases, its pressure also increases, assuming that the volume stays the same. This happens because the gas molecules gain energy. This extra energy causes them to move faster and collide more frequently with each other and with the sides of a container.
A can of spray paint contains paint and gas under pressure. When the nozzle on the top of the can is pressed, several things happen. Some of the gas escapes, blowing the paint out and the can becomes cold. Which of the following statements would best explain why the can becomes cold?
|A)||As the gas pressure decreases, its temperature drops.|
|B)||The liquid in the spray cools the can.|
|C)||The gas exists at a higher temperature than the liquid.|
|D)||Liquids exist at more constant temperatures than gases do.|
|E)||As the liquid is compressed, its temperature drops.|
Preserving food by radiation has been practiced on a small scale for twenty years. As this process is used on more foods, public attention is beginning to focus on it.
Below are five statements about using radiation to preserve food. Which of these statements is an opinion rather than a fact?
|A)||Food exposed to radiation does not become radioactive.|
|B)||Radiation may change the texture of the food.|
|C)||Radiation will not eliminate the need for insect sprays in the fields.|
|D)||Radiation slows the ripening of some fruits and vegetables.|
|E)||Because its long-range effects are unpredictable, radiation should be banned.|