Energy of a Photon
Calculate the energy of one photon of yellow light that has a wavelength of 589 nm.
(a) A laser emits light that has a frequency of 4.69 × 1014 s-1. What is the energy of one photon of this radiation?
(b) If the laser emits a pulse containing 5.0 × 1017 photons of this radiation, what is the total energy of that pulse? (c) If the laser emits 1.3 × 10-2 J of energy during a pulse, how many photons are emitted?
Chapter 10 Thursday, March 31, 20169:59 AM What is Public Opinion • Citizens' attitudes about political issues, leaders, institutions, and events • May be understood on two levels: o Individual: what one person thinks about issues, leaders, institutions, and events o Aggregate: the accumulation of these individual beliefs as expressed in polls, votes, town meetings, protests, etc • Preferences, beliefs, and choices matter Preferences, Beliefs, and Choices • Preferencesare shaped by economic sel-‐‑f interest and social or moral values; some preferences may be held more firmly than others • Beliefs reflect how people understand the world and the consequences of actions • The choicespresented to us do not always yield a clear measure of our preferences or beliefs Variety of Opinion • Americans do hold common opinions on some issues, like equality of opportunity, but on most of them, the public does not hold a single view • What we're interested in knowing: o Evaluations of individuals and institutions some issues, like equality of opportunity, but on most of them, the public does not hold a single view • What we're interested in knowing: o Evaluations of individuals and institutions o Assessments of public choices o Assessments of current circumstances o Political orientations Origins of Nature of Opinion • Individual opinions are a products of one's personality, social characteristics, and interests Opinions are also shaped by institutional, • political, and governmental forces that make it more likely we'll hold some belief and less likely we'll hold others Foundations of Preferences • Self-‐‑Interest: Government policies directly affect our financial wel-‐‑lbeing, the quality of public services, and public safety • Values: Our philosophies about morality and justice affect our opinions and may even contradict our economic interests • Social Groups -‐‑ Our family, neighborhood, language, race, and religion also have an impact on our preferences Socialization • A process through which individuals assimilate community preferences and norms through social interactions • Important agents of socialization: o Family o Education o Work o Social Groups o Political Conditions Political Ideology o Education o Work Social Groups o o Political Conditions Political Ideology • Ideology is a comprehensive way of understanding political or cultural situations. It is a set of assumptions about the way the world and society works that help us organize our beliefs, information, and new situations • Most Americans describe themselves as either liberals or conservatives Identity Politics • Political identities are distinctive characteristics or group associations that individuals carry and that hold for those individuals' social connections or common values and interests with others in that group • Identities are both psychological and sociological • Unlike ideologies, identities are absolutes Range of Social, Cultural, and Political Identities • Nationality • Partisan Identification • Race/ Ethnicity • Gender • Religion • Geography • Outgroups Race and the Public Opinion • The history of slavery and racial • Geography • Outgroups Race and the Public Opinion • The history of slavery and racial discrimination has created a deep, lasting divide between whites, on the one hand, and blacks and Latinos on the other • There are stark differences in beliefs and preferences among Latinos, blacks, and whites regarding the basic responsibilities of government Gender and the Public Opinion • Gender gap: a distinctive pattern of voting behavior reflecting the differences in views between women and men • The gender gap has been an enduring feature of American elections for some time, with women consistently voting more Democratic and men voting more Republican Religion, Geography, and the Public Opinion • Religion shapes peoples' values and beliefs and also serves as a strong identity • Where we live also molds our sense of identity. Regional accents, states pride, and history all play a role Outgroups and Public Opinion • Some groups are defined not by who they are but by who they are not; they are the outgroups • Political, social, and economic discrimination is not limited to race, ethinicity, gender, and religion Public Opinion and • Political, social, and economic discrimination is not limited to race, ethinicity, gender, and religion Public Opinion and Political Knowledge Thursday, March 31, 2016 10:08 AM • Few Americans devote sufficient time, energy, or attention to politics to really understand all the issues • The costs of gathering information may be high and the benefits may be low • We can think of examples, however, in which low levels of political information can be harmful to groups of people • Knowledge and instability: Low levels of information lead to instability and incoherence in responses to surveys • Others argue there is great stability in public opinion Shaping Opinion: Government and Politicians Thursday, March 31, 2016 • All governments attempt to influence citizens' beliefs, but their efforts are counteracted by interest groups, media, and politicians opposed to those in power • Presidents have been actively "going public" for decades to influence how the public perceives their policy initiatives • They are not always successful, power • Presidents have been actively "going public" for decades to influence how the public perceives their policy initiatives • They are not always successful, however Shaping Opinion: Private Groups Thursday, March 31, 2016 • Following the Rationality Principle, groups and individuals seek to influence latent, unorganized individuals to support their cause • Groups and individuals with more money, institutional support, and skill will have more success Shaping Opinion: Media Thursday, March 31, 2016 • The mass media are the conduits through which most politically relevant information flows to the public • Traditional media sources -‐ newspapers, radio and television -‐are supplemented today by the internet and social media • We learn from the media actively (seeking out news) and passively (absorbing news through entertainment) • We learn from the media actively (seeking out news) and passively (absorbing news through entertainment) Media Effects: Agenda-‐Setting, Priming, and Framing Thursday, March 31, 2016 • Agenda Setting -‐the power to bring attention to particular issues and problems • Priming -‐ the process of preparing the public to take a particular view of an event or a political actor • Framing -‐ the power of the media to influence how events and issues are interpreted Measuring Public Opinion Thursday, March 31, 2016 • A poll is a scientific instrument for measuring public opinion • A century ago, political leaders utilized imperfect measures of public opinion such as crowd size and the applause they could hear • Political leaders use polls to determine weather to run for office, what policies to support, and how to make appeals Measuring Public Opinion: Samples and how to make appeals Measuring Public Opinion: Samples Thursday, March 31, 2016 10:48 AM • A sample is a small group selected to represent the most important characteristics of an entire population • In order to get a random sample in national polls, pollsters often use random-‐digit dialing, in which a random-‐number generator produces a list of as many 10 -‐digit phone numbers as the pollster deems necessary Measuring Public Opinion: Selection Bias Thursday, March 31, 2016 • An accurate survey result requires we have a representative sample of the larger population • Finding a representative sample is not easy, and we have to avoid selection bias -‐ a polling error in which the sample is not representative of the population being studied Measuring Public Opinion: Sample Size Thursday, March 31, 2016 • The reliability of a poll is also Measuring Public Opinion: Sample Size Thursday, March 31, 2016 • The reliability of a poll is also partly a function of sample size • The larder the sample size, the less likely the result will be due to sampling error -‐ a polling error that arises on account of small sample size • But larger samples are more expensive Measuring Public Opinion: Survey Design Thursday, March 31, 2016 11:05 AM • Even with a large, representative sample, a poll may provide a misleading result or measurement error • Measurement error is the failure to identify the true distribution of opinion within a population because of errors such as ambiguous or poorly worded questions How does Public Opinion Influence Government Policy Thursday, March 31, 2016 11:08 AM • 4 important ways: ○ Electoral accountability ○ Building coalitions: Public Government Policy Thursday, March 31, 2016 11:08 AM • 4 important ways: ○ Electoral accountability ○ Building coalitions: Public bills are more likely to pass if they have public support ○ Input in rule making and legal decisions ○ Shaping public opinion: Political leaders' behavior is changes as they seek to shape public opinion