Cho dòng điện thẳng dài vô hạn có cường độ không đổi I 1 = 5A chạy qua và dòng điện I 2 = 10A chạy trong khung dây hình chữ
nhật theo chiều ABCD có cạnh bằng a = 30cm và b = 50cm . Cạnh AB
song song với dòng điện, cách dòng điện một khoảng R . Hãy xác định
từ lực tác dụng lên từng cạnh của khung. Cho uy = 1. uy 0 = 4.pi..10 -7 H/m.

Distinguish between a transverse wave and a longitudinal wave.

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

The solar panels used by mark function because of the photoelectric effect. light shines on the cells causing electrons to be ejected from the metal, which produces an electric current. at night on mars, no light will fall on the solar cells and no electric current will be generated. according to your notes, what type of light is typically needed to cause the photoelectric effect? a)visible b)ultraviolet c)infrared