Plz tell me the answer of the 13th question .

(I)
firstly , we will find maximum and minimum y-value
we can see that
maximum value is 5
minimum value is -5
so, we can find amplitude
[tex] A=\frac{5-(-5)}{2} [/tex]
[tex] A=5 [/tex]..........Answer
(II)
we know that
wave length is the length of one wave
we can see that from B to F , there is one wave
and we are given it's length as 20cm
so, wavelength is 20cm......Answer
(III)
we know that
[tex] velocity=wavelength*frquency [/tex]
we are given
frequency =100hz
wavelength =20cm
now, we can find velocity
[tex] velocity=20*100cm/sec [/tex]
[tex] velocity=2000cm/sec [/tex]............Answer