The diagram shows a trace of a wave on a cathode-ray oscilloscope.

The vertical and horizontal gridlines have a spacing of 1.0cm. The voltage scaling is 4Vcm–1 and

the time scaling is 5ms cm–1.

1cm

1cm

What are the amplitude and period of the wave?

amplitude/V period/ ms

A 1.5 4

B 5.0 10

C 6.0 20

D 12.0 20