Question

Two waves have amplitudes of 10 m and 7 m, respectively. What are the maximum and minimum amplitudes of the resultant wave if they interfere first constructively, and then destructively?
a. 10 m and 3 m
b. 17 m and 0 m
c. 17 m and 3 m
d. 70 m and 1.4 m

Answer 1

Regarding amplitude, we have that these are properties that can be added or subtracted from each other. We are given the amplitude of two waves, their absolute value of the sum or subtraction will give us the minimum and maximum value, our values are determined as

$A_1 = 10m$

$A_2 = 7m$

Therefore the maximum value will be,

$A_{max} = |A_1+A_2|$

$A_{max} = |10+7|$

$A_{max} = 17m$

And the minimum value will be,

$A_{min} = |A_1-A_2|$

$A_{min} = 10-7$

$A_{min} = 3m$

Therefore the correct option is C.