Mặt phẳng rất rộng, tích điện đều Q > 0. So sánh điện thế V do mặt phẳng

gây ra tại các điểm A, B, C.

A. VA = VB = VC.

B. VA > VB > VC.

C. VA = VB > VC.

D. VA = VB < VC.

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.

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

A248-g piece of copper is dropped into 390 ml of water at 22.6 °c. the final temperature of the water was measured as 39.9 °c. calculate the initial temperature of the piece of copper. assume that all heat transfer occurs between the copper and the water. remember, the density of water is 1.0 g/m