A sound wave is transmitted from liquid P into liquid Q. Its frequency is 1.2 kHz1.2\ \mathrm{kHz}1.2 kHz and its wavelength in P is 1.0 m. The speed in Q is 1500 m/s.
Which gives the frequency in Q and the percentage increase in wavelength?
1500 Hz1500\ \mathrm{Hz}1500 Hz and 25%25\%25%
1200 Hz1200\ \mathrm{Hz}1200 Hz and 20%20\%20%
1200 Hz1200\ \mathrm{Hz}1200 Hz and 25%25\%25%
1500 Hz1500\ \mathrm{Hz}1500 Hz and 20%20\%20%