An opera singer who is a baritone, lowers his pitch and raises his voice for a song. Which best describes how the resulting sound wave has changed? The sound wave will have: a lower amplitude and higher wavelength

a lower amplitude and higher frequency.

a higher amplitude and lower frequency.

a higher amplitude and faster speed

3.

Explanation:

The correct answer is a higher amplitude and lower frequency. Since an opera singer is lowering his pitch it means that he is creating higher amplitude and because he is raising his voice for a song with that higher amplitude he is creating lower frequency.

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.