Final answer:
Receptacles in a bedroom must be placed so that no point along the floor is more than 6 feet from a receptacle, as per the NEC in the United States. This facilitates safe and easy access to electricity. The common ac voltages in the US and Europe are 120 V and 220 V, respectively.
Step-by-step explanation:
When laying out the wall receptacle locations in a bedroom in a house, the National Electrical Code (NEC) in the United States specifies that receptacles should be installed so that no point along the floor line is more than 6 feet (1.8 meters) from a receptacle. This requirement is part of ensuring that electrical power sources are adequately distributed within a room to reduce the need for unsafe extension cords and allows easy access to electricity for appliances and devices commonly found in bedrooms.
The ac voltages and frequencies typically used in home installations vary by country. In the United States, the potential difference between the two sides of an electrical outlet alternate with a frequency of 60 Hz and an amplitude of 170 V, leading to a common voltage rating of 120 V. In Europe, the frequency is usually 50 Hz with an amplitude of 311 V, resulting in a common voltage of 220 V.