Question

Two periodic waves of intensities `I_(1)` and `I_(2)` pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is:
A. `(l_(1)+l_(2))`
B. `2(l_(1)+l_(2))`
C. `(sqrt(l_(1))+sqrt(l_(2)))`
D. `(sqrt(l_(1))-sqrt(l_(2)))`

Answer 1

Correct Answer - B
We know that,
`l_(max)=(a_(1)+a_(2))^(2)` . . .(i)
`l_(min)=(a_(1)-a_(2))^(2)` . . .(ii)
On adding Eqs. (i) and (ii) we, get
`l_(max)+l_(min)=(a_(1)+a_(2))^(2)+(a_(1)-a_(2))^(2)`
`l_(max)+l_(min)=a_(a)^(2)+a_(2)^(2)+2a_(a)a_(2)+a_(a)^(2)+a_(2)^(2)-2a_(1)a_(2)`
`l_(max)+l_(min)=2(a_(1)^(2)+a_(2)^(2))`
But `lpropa^(2)`
Therefore, `l_(max)+l_(min)=2(l_(1)+l_(2))`