Question

Literacy 1. Why is a parallel connection is used in houses? Why is a series connection not used in houses? 2. Electric kettle uses 10 Amperes current. You plug in three kettles at once. How many Amperes do you need? Is it safe to use many devices? Is there any danger? 3. Electric kettle uses 10 Amperes and 220 Volts. You plug in three kettles. What is the equivalent resistance of three kettles? Why is it lower than a resistance of one kettle?помогите​

Answer 1

Объяснение:

1. Все приборы рассчитаны на одинаковое бытовое напряжение. Параллельное соединение приборов обеспечивает одинаковое напряжение на них. Если приборы соединить последовательно, то напряжение на них будет разное, что приведет к неверной работе приборов или их поломке.

2. Одновременное подключение трех чайников, потребляющих по 10 Ампер каждый, создаст силу тока в цепи 30 Ампер (это следует из законов параллельного соединения: I = I1 + I2 + I3). Это довольно большая сила тока. Опасность такого подключения завизит от толщины проводов, которыми выполнена электрическая сеть. Если провод достаточно толстый, то его сопротивление невелико, и он не будет испытывать серьёзных проблем. Но, если толщина провода недостаточна, то его сопротивление становится больше, и провод довольно сильно греется. Это может привести к оплавлению изоляции и короткому замыканию. Короткое замыкание может привести к возгоранию и пожару. Чтобы этого не произошло, в сети существует специальный выключатель-автомат, который отключает подачу электроэнергии, если сила тока превышает безопасный уровень.

3. Сопротивление одного чайника по закону Ома будет равно: R1 = U/I = 220V / 10A = 22 Ohm

Если чайники включить параллельно, то по закону параллельного соединения получим:

1/R = 1/R1 + 1/R2 + 1/R3

1/R = 3/22

R = 22/3 Ohm = 7⅓ Ohm (7,333333.... Ohm)

Answer 2

1. Parallel Connection in Houses: Parallel connections are used in houses for electrical circuits because they offer several advantages over series connections:

   a. Voltage Remains Constant: In a parallel connection, each device or appliance is connected directly to the power source (e.g., a wall outlet). This means that each device receives the full voltage (e.g., 120V or 220V), ensuring they operate at their intended voltage. In a series connection, the voltage is divided among the devices, which can result in insufficient voltage for proper operation.

   b. Independence: In a parallel connection, each device operates independently of the others. If one device fails or is disconnected, the others continue to function. In a series connection, if one device fails or is disconnected, the entire circuit is interrupted.

   c. Safety: Parallel circuits are safer because if there is a fault in one device, it doesn't affect the others. In a series connection, if one device develops a fault, the entire circuit is compromised.

   2. Using Three Electric Kettles: If one electric kettle uses 10 Amperes of current, and you plug in three of them simultaneously, you would need 30 Amperes in total (10 Amperes per kettle × 3 kettles = 30 Amperes). However, a typical household electrical circuit is usually rated for 15-20 Amperes in the United States, and it's typically safer to avoid drawing the full rated current for an extended period.

   Using multiple high-current devices simultaneously can overload your electrical circuit, causing circuit breakers to trip or fuses to blow. This is a safety feature designed to prevent overheating and potential fire hazards. To use multiple devices like electric kettles safely, you may need to distribute them across different circuits or use them one at a time.

   3. Equivalent Resistance of Three Kettles: When you connect resistors (like electric kettles) in parallel, the equivalent resistance (R_eq) is calculated using the formula:

   1 / R_eq = 1 / R1 + 1 / R2 + 1 / R3

   In this case, if each electric kettle has a resistance of R (one kettle's resistance), and you connect three in parallel, the equivalent resistance would be lower than a single kettle. This is because adding more parallel paths reduces the overall resistance.

   R_eq = 1 / (1 / R + 1 / R + 1 / R) R_eq = 1 / (3 / R) R_eq = R / 3

   So, the equivalent resistance of three kettles connected in parallel is one-third of the resistance of a single kettle. This is why the equivalent resistance is lower when you parallel connect them.

   However, in the context of real electrical appliances, the resistance of an electric kettle is not a common parameter given; instead, its power rating is typically provided in watts or kilowatts.