What is an example of a wave that is not mechanical and how is it different?

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire

The atoms in a nickel crystal vibrate as harmonic oscillators with an angular frequency of 2.3 × 1013 rad/s. the mass of a nickel atom is 9.75 × 10-26 kg. what is the difference in energy between adjacent vibrational energy levels of nickel? (h = 6.626 × 10-34 j • s, , 1 ev = 1.60 × 10-19 j)

Which compound is held together by the electrostatic force between two ions? a. co2 b. cci4 c. h2s d. mgf2