*Question*
Answer the following question given this paragraph: 27.5 Single Slit Diffraction Light passing through a single slit forms a diffraction pattern somewhat different from those formed by double slits or diffraction gratings. Figure 27.21 shows a single slit diffraction pattern. Note that the central maximum is larger than those on either side, and that the intensity decreases rapidly on either side. In contrast, a diffraction grating produces evenly spaced lines that dim slowly on either side of center. Q: What kind of lines does a diffraction grating produce? Choices: - nearly spaced lines - properly spaced lines - randomly spaced lines - evenly spaced lines A:
**Answer**
evenly spaced lines

*Question*
Answer the following question given this paragraph: Liquefaction of Gases Liquefaction of gases is the condensation of gases into a liquid form, which is neither anticipated nor explained by the kinetic molecular theory of gases. Both the theory and the ideal gas law predict that gases compressed to very high pressures and cooled to very low temperatures should still behave like gases, albeit cold, dense ones. As gases are compressed and cooled, however, they invariably condense to form liquids, although very low temperatures are needed to liquefy light elements such as helium (for He, 4.2 K at 1 atm pressure). Liquefaction can be viewed as an extreme deviation from ideal gas behavior. It occurs when the molecules of a gas are cooled to the point where they no longer possess sufficient kinetic energy to overcome intermolecular attractive forces. The precise combination of temperature and pressure needed to liquefy a gas depends strongly on its molar mass and structure, with heavier and more complex molecules usually liquefying at higher temperatures. In general, substances with large van der Waals acoefficients are relatively easy to liquefy because large a coefficients indicate relatively strong intermolecular attractive interactions. Conversely, small molecules with only light elements have small a coefficients, indicating weak intermolecular interactions, and they are relatively difficult to liquefy. Gas liquefaction is used on a massive scale to separate O2, N2, Ar, Ne, Kr, and Xe. After a sample of air is liquefied, the mixture is. Q: Liquefaction ccurs when the molecules of a gas are cooled to the point where they no longer possess sufficient kinetic energy to overcome what? Choices: - intermolecular gravitational forces - gravitational attractive forces - bonding attractive forces - intermolecular attractive forces A:
**Answer**
intermolecular attractive forces

*Question*
Answer the following question given this paragraph: Q: What is the term for the basic contractile unit of the muscle? Choices: - filament - sphincter - bandimere - sarcomere A:
**Answer**
sarcomere

*Question*
Answer the following question given this paragraph: Electrons are located at fixed distances from the nucleus, called energy levels. You can see the first three energy levels in the Figure below . The diagram also shows the maximum possible number of electrons at each energy level. Q: Electrons are located at fixed distances from the nucleus, what are they called? Choices: - Energy layers - Positive levels - energy concentrations - energy levels A:
**Answer**
energy levels