Problem: Antenna (radio):

The net quality of a ground reflection depends on the topography of the surface. When the irregularities of the surface are much smaller than the wavelength, we are in the regime of specular reflection, and the receiver sees both the real antenna and an image of the antenna under the ground due to reflection. But if the ground has irregularities not small compared to the wavelength, reflections will not be coherent but shifted by random phases. With shorter wavelengths (higher frequencies), this is generally the case.

When will reflections not be coherent?
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A: ground has irregularities


Problem: Railway electrification system:

The first attempts to use standard-frequency single-phase AC were made in Hungary as far back as 1923, by the Hungarian Kálmán Kandó on the line between Budapest-Nyugati and Alag, using 16 kV at 50 Hz. The locomotives carried a four-pole rotating phase converter feeding a single traction motor of the polyphase induction type at 600 to 1,100 V. The number of poles on the 2,500 hp motor could be changed using slip rings to run at one of four synchronous speeds. The tests were a success so, from 1932 until the 1960s, trains on the Budapest-Hegyeshalom line (towards Vienna) regularly used the same system. A few decades after the Second World War, the 16 kV was changed to the Russian and later French 25 kV system.

What type of the converter was used in hungarian locomotives of that time?
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A: four-pole rotating phase converter


Problem: Somalis:

In the Somali diaspora, multiple Islamic fundraising events are held every year in cities like Birmingham, London, Toronto and Minneapolis, where Somali scholars and professionals give lectures and answer questions from the audience. The purpose of these events is usually to raise money for new schools or universities in Somalia, to help Somalis that have suffered as a consequence of floods and/or droughts, or to gather funds for the creation of new mosques like the Abuubakar-As-Saddique Mosque, which is currently undergoing construction in the Twin cities.

Along with Minneapolis, London and Birmingham, what city contains a notable population of Somalis?
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A: Toronto


Problem: Windows 8:

New features and functionality in Windows 8 include a faster startup through UEFI integration and the new "Hybrid Boot" mode (which hibernates the Windows kernel on shutdown to speed up the subsequent boot), a new lock screen with a clock and notifications, and the ability for enterprise users to create live USB versions of Windows (known as Windows To Go). Windows 8 also adds native support for USB 3.0 devices, which allow for faster data transfers and improved power management with compatible devices, and hard disk 4KB Advanced Format support, as well as support for near field communication to facilitate sharing and communication between devices.

What is Windows to Go?
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A:
live USB versions of Windows