An opera singer breaks a crystal glass with her voice. which best explains why this occurs? 1. the pitch of her voice matches the pitch of the glass. 2. the amplitude of her voice heats the glass until it breaks. 3. the intensity of her voice produces a standing wave in the glass. 4. the frequency of her voice matches the natural frequency of the glass.

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.

1.what is where an object is located 2. what is how fast an objects speed is changing 3. what is how fast an object is moving

Ultraviolet radiation is dangerous because it has a high enough energy to damage skin cells. what is the best explanation of the relationship between wavelength and wave energy? a) wave energy is related only to frequency, not wavelength. b) longer wavelengths have lower frequencies but higher energy. c) the shorter the wavelength, the lower the frequency and the higher the energy. d) the shorter the wavelength, the higher the frequency and the higher the energy.