Two loudspeakers, a and b are driven by the same amplifier
andemit sinusoidal waves in phase. speaker b is 2.00 m to theright
of speaker a. consider point q along the extension ofthe line
connecting the speakers, 1.00 m to the right of speakerb. both
speakers emit sound waves that travel driectly fromthe speaker to
point q.

Q)Two loudspeakers, A and B, are driven by the same amplifier as shown and emit sinusoidal waves in phase. Speaker B is 2.00 m to the right of speaker A. Consider point Q along the extension of the line connecting the speakers, 1.00 m to the right of speaker B. Both speakers emit sound waves that travel directly from the speaker to point Q. a) What is the lowest frequency for which constructive interference occurs at point Q? b) What is the lowest frequency for which destructive interference occurs at point Q? The speed of sound wave is 344 m/s.

lowest frequency is 172 Hz. for n = 1

lowest frequency is 86 Hz for n = 0

Explanation:

(a) Constructive interference takes place when the path difference is n where n=1,2,3 ...

frequency f = v /λn

                      = v n / d  

                       = n ( 344 / 2 )

                       = n ( 172 ) Hz.

lowest frequency is 172 Hz

b)Destructive interference takes place when the path difference is n/2 x  where n=1,3,5 ...

λ = 4/2n+1

for n = 0

λ = 4m

f = 344/4

f = 86 Hz.

lowest frequency is 86 Hz

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia