Hai điện tích điểm bằng nhau đặt trong chân không cách nhau một khoảng R1 = 4 cm lực đẩy giữa chúng là F1 = 9 nhân 10 mũ trừ 5 niutơn để lực tác dụng giữa chúng là F2 = 1,6 nhân 10 mũ trừ 4 n thì khoảng cách R2 giữa điện tích đó phải bằng bao nhiêu

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?

The ozone hole appears in antarctica during

Aloop of wire is in a magnetic field such that its axis is parallel with the field direction. which of the following would result in an induced emf in the loop? choose all that apply. a loop of wire is in a magnetic field such that its axis is parallel with the field direction. which of the following would result in an induced emf in the loop? choose all that apply. moving the loop outside of the magnetic field region. spin the loop such that its axis does not consistently line up with the magnetic field direction. change the magnitude of the magnetic field. change the diameter of the loop