1) a piano tuner is testing a wire currently under 2000 n tension. the wire is 1.5 m long and has a mass of 20 g. if the tuner's computer can detect a maximum frequency of 10,000 hz, what is the highest harmonic number the computer can detect (1 point) a) 77 b) 100 c) 25 d) 63 2) a wave is traveling with a speed of 400 m/s and it has a wavelength of 28 m. what will the frequency of the wave be if the wavelength is doubled but the speed remains the same? (1 point) a) 9.09 hz b) 14.3 hz c) 21.7 hz d) 7.14 hz 3) if a standing wave is vibrating in it's third harmonic, how many nodes does it have? (1 point) a) 4 b) 3 c) 2 d) 1 4) an organ pipe, which is a pipe closed at one end, is 2.46 m long and the speed of sound in air in that pipe is 345 m/s. what is the frequency of the fundamental harmonic in this pipe? (1 point) a) 44.9 hz b) 20.6 hz c) 35.1 hz d) 13.2 hz 5) using the same organ pipe from question 11, how many possible harmonics are there in the normal human hearing range of 20 hz to 20,000 hz? (1 point) a) 570 b) 985 c) 101 d) 47 6) a standing wave is set up on a violin string to produce a note of a sharp contra (58 hz). the violin string is 32 cm long. if the sound is produced in the fundamental frequency, what is the speed of the wave moving across the string? (1 point) a) 52.78 m/s b) 18.83 m/s c) 20.01 m/s d) 37.12 m/s

1.

N = 77

Explanation:

1) As we know that Tension in the wire is given as

T = 2000 N

now mass per unit length of the wire is given as

Now fundamental frequency is given as

now highest frequency is given as 10000 Hz

so total harmonics is given as

2.

D) 7.14 Hz

Explanation:

As we know that

speed = (frequency)(wavelength)

given that

speed = 400 m/s

wavelength = 28 m

so frequency is given as

now if wavelength is doubled then we will have

new frequency will be

3.

Number of nodes = 4

A) 4

Explanation:

Number of nodes = number of harmonics + 1

so here we know that

number of harmonics = 3

Number of nodes = 3 + 1

Number of nodes = 4

4.

C) 35.1 Hz

Explanation:

fundamental frequency in an organ pipe closed at one end is given as

here we know that

v = 345 m/s

L = 2.46 m

now we have

5.

A) 570

Explanation:

Number of harmonics is given as

6.

Explanation:

For fundamental frequency we know that

here we know that

now we have

its a 5.5 n

glad that

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