Moscow is the capital of the Russian Federation and the administrative center of the Moscow region, it is also the largest Russian city with over 12 million residents. Moscow is located on the Moskva River in the European part of the country. Most historians agree that this river gave its name to the city. The Moscow Metro is considered to be one of the most beautiful underground systems in the world. Indeed, many of the stations have beautiful murals on the walls.There are many theaters, monuments, parks, squares and theaters in Moscow. For example, there are more than 150 theaters that produce shows of various genres (the Taganka Theater, Lenkom Theatre, Sovremennik Theater). Moscow offers an exciting nightlife. A lot of the clubs open their doors for people who want to relax and dance all night.
Объяснение:
1. R=U:I R=220В:4А=55 Ом
l=RS:r l=55 Ом*0.1 мм2:1.1 Ом*мм2/м=5м
ответ: l=5м2. A=UIt
9кДж=9*10^3 Дж
15мин=900с
U=A/It
U=9*10^3/(900c*2А)=5В
R=U/I=5В/2А=2,5Ом
3. На электрический заряд,движущийся в магнитном поле действует сила лоренца:F=q*v*B*sina ,где q=1.6*10^-19 кл -заряд протона.
Вычислим:F=1.6*10^-19*2*10^6*0.1*05=1.6*10^-14H 4. -5. длина волны = скорость волны,поделённая на частоту волны
нужно перевести км/с в м/с,МГц - в Гц,и подставить в эту формулу