Article: Most types of capacitor include a dielectric spacer, which increases their capacitance. These dielectrics are most often insulators. However, low capacitance devices are available with a vacuum between their plates, which allows extremely high voltage operation and low losses. Variable capacitors with their plates open to the atmosphere were commonly used in radio tuning circuits. Later designs use polymer foil dielectric between the moving and stationary plates, with no significant air space between them.

Question: What do many capacitors contain that raises the capacitance?
Ans: a dielectric spacer

Article: Despite the calamity and huge death toll, Lisbon suffered no epidemics and within less than one year was already being rebuilt. The new city centre of Lisbon was designed to resist subsequent earthquakes. Architectural models were built for tests, and the effects of an earthquake were simulated by marching troops around the models. The buildings and big squares of the Pombaline City Centre still remain as one of Lisbon's tourist attractions. Sebastiao de Melo also made an important contribution to the study of seismology by designing an inquiry that was sent to every parish in the country.

Question: What type of natural disaster was the city center of Lisbon designed to resist?
Ans: earthquakes

Article: Switzerland's most important economic sector is manufacturing. Manufacturing consists largely of the production of specialist chemicals, health and pharmaceutical goods, scientific and precision measuring instruments and musical instruments. The largest exported goods are chemicals (34% of exported goods), machines/electronics (20.9%), and precision instruments/watches (16.9%). Exported services amount to a third of exports. The service sector especially banking and insurance, tourism, and international organisations is another important industry for Switzerland.

Question: What percentage of exports are exported services?
Ans: a third

Article: Napoleon III, since the Crimean War Britain's closest ally, visited London in April 1855, and from 17 to 28 August the same year Victoria and Albert returned the visit. Napoleon III met the couple at Dunkirk and accompanied them to Paris. They visited the Exposition Universelle (a successor to Albert's 1851 brainchild the Great Exhibition) and Napoleon I's tomb at Les Invalides (to which his remains had only been returned in 1840), and were guests of honour at a 1,200-guest ball at the Palace of Versailles.

Question: When did Napoleon III visit London?
Ans:
April 1855