For water, which takes more energy, melting or evaporating?

Wo audio speakers are placed on a vertical rail. speaker a is placed at head-level while speaker b is place at some variable height, \delta yδy, above speaker a. both speakers receive simultaneous input from a sine-wave generator so the speakers each produce a pure sinusoidal sound wave with a wavelength of 0.531 meters. calculate the lowest height that speaker b can be placed above speaker a to produce a minimum of sound heard by person standing \delta x = 7.86δx=7.86 meters directly in front of speaker a.

In the first law of thermodynamics, triangle e=q-w, what does q stand for

The diagram shows four locations in the electric field of a positive point charge m. at which location is the electric potential the greatest.