Đặt vào 2 đầu R1 hiệu điện thế U1=60V thì I1=2,5A .Đặt vào 2 đầu R2 hiệu điện thế U2=U1 thì I2=7,5 A .So sánh R1 và R2

Answer quickly (15 points) a comet is approaching earth. describe earth’s gravitational pull as the comet gets closer to it. a. remain constant b. increase c. decrease d. reversed

Glass is transparent to visibile light under normal conditions; however, at extremely high intensities, glass will absorb most of the light incident upon it. this works through a process known as multiphoton absorption. in this process, several photons are absorbed at the same time. if very intense light whose photons carry 2ev of energy is shined onto a material with a band gap of 4ev, that light can be absorbed through two-photon absorption, because two photons have the right amount of energy to bridge the band gap. what is the minimum number of photons of 800-nm light that are needed to equal or exceed the band gap of fused silica glass

Describe how the motion of a spring being pushed forward and backward is similar to the motion of air particles in a sound wave.