<u>Answer :</u>
(a) d = 0.25 m
(b) d = 0.5 m
<u>Explanation :</u>
It is given that,
Frequency of sound waves, f = 686 Hz
Speed of sound wave at
is, v = 343 m/s
(1) Perfectly destructive interference occurs when the path difference is half integral multiple of wavelength i.e.
........(1)
Velocity of sound wave is given by :




Hence, when the speakers are in phase the smallest distance between the speakers for which the interference of the sound waves is perfectly destructive is 0.25 m.
(2) For constructive interference, the path difference is integral multiple of wavelengths i.e.
( n = integers )
Let n = 1
So, 


Hence, the smallest distance between the speakers for which the interference of the sound waves is maximum constructive is 0.5 m.
Answer:
The uncertainty in the location that must be tolerated is 
Explanation:
From the uncertainty Principle,
Δ
Δ

The momentum P
= (mass of electron)(speed of electron)
= 
= 
If the uncertainty is reduced to a 0.0010%, then momentum
= 
Thus the uncertainty in the position would be:
Δ
Δ
Explanation:
F =(frac{1}{4{pi}{varepsilon}_o}) x (frac {q_1q_2}{r^2})
F =(frac {5 {times} 10 {times} 8 {times} 10}{0.002 {times} 0.002}) x 9 x 10
F = 900N