QUES: Film speed is found from a plot of optical density vs. log of exposure for the film, known as the Dlog H curve or HurterDriffield curve. There typically are five regions in the curve: the base + fog, the toe, the linear region, the shoulder, and the overexposed region. For black-and-white negative film, the "speed point" m is the point on the curve where density exceeds the base + fog density by 0.1 when the negative is developed so that a point n where the log of exposure is 1.3 units greater than the exposure at point m has a density 0.8 greater than the density at point m. The exposure Hm, in lux-s, is that for point m when the specified contrast condition is satisfied. The ISO arithmetic speed is determined from:
What is the ISO arithmetic speed?

ANS: unanswerable

QUES: Capacitors may retain a charge long after power is removed from a circuit; this charge can cause dangerous or even potentially fatal shocks or damage connected equipment. For example, even a seemingly innocuous device such as a disposable-camera flash unit, powered by a 1.5 volt AA battery, has a capacitor which may contain over 15 joules of energy and be charged to over 300 volts. This is easily capable of delivering a shock. Service procedures for electronic devices usually include instructions to discharge large or high-voltage capacitors, for instance using a Brinkley stick. Capacitors may also have built-in discharge resistors to dissipate stored energy to a safe level within a few seconds after power is removed. High-voltage capacitors are stored with the terminals shorted, as protection from potentially dangerous voltages due to dielectric absorption or from transient voltages the capacitor may pick up from static charges or passing weather events.
To what voltage could a capacitor from a disposable camera be charged to?

ANS: over 300 volts

QUES: The Kerrytown Shops, Main Street Business District, the State Street Business District, and the South University Business District are commercial areas in downtown Ann Arbor. Three commercial areas south of downtown include the areas near I-94 and Ann Arbor-Saline Road, Briarwood Mall, and the South Industrial area. Other commercial areas include the Arborland/Washtenaw Avenue and Packard Road merchants on the east side, the Plymouth Road area in the northeast, and the Westgate/West Stadium areas on the west side. Downtown contains a mix of 19th- and early-20th-century structures and modern-style buildings, as well as a farmers' market in the Kerrytown district. The city's commercial districts are composed mostly of two- to four-story structures, although downtown and the area near Briarwood Mall contain a small number of high-rise buildings.
Which area in the city is composed mostly of two-to-three story buildings?

ANS: unanswerable

QUES: The centre of Southampton is located above a large hot water aquifer that provides geothermal power to some of the city's buildings. This energy is processed at a plant in the West Quay region in Southampton city centre, the only geothermal power station in the UK. The plant provides private electricity for the Port of Southampton and hot water to the Southampton District Energy Scheme used by many buildings including the WestQuay shopping centre. In a 2006 survey of carbon emissions in major UK cities conducted by British Gas, Southampton was ranked as being one of the lowest carbon emitting cities in the United Kingdom.
What source of geothermal power sits below Southampton's center?

ANS:
hot water aquifer