Acrying baby emits sound with an intensity of 8.0 × 10-8 w/m2. calculate a reasonable estimate for the intensity level from a set of quintuplets (five babies), all crying simultaneously at the same place? the lowest detectable intensity is 1.0 × 10-12 w/m2.

The intensity level from a set of quintuplets (five babies) : 56 dB

Wave intensity is the power of a wave that is moved through a plane of one unit that is perpendicular to the direction of the wave

Can be formulated

I = intensity, W m⁻²

P = power, watt

A = area, m²

The farther the distance from the sound source, the smaller the intensity

So the intensity is inversely proportional to the square of the distance from the source

Intensity level (LI) can be formulated

Io = 10⁻¹²

For the level of intensity of several sound sources as many as n pieces can be formulated:

The intensity level of 1 baby is

LI = 10 log 8.10⁴

LI = 49

The intensity level of 5 babies :

LI5 = LI + 10 log n

LI5 = 49 + 10 log 5

LI5 = 49 + 7

LI5 = 56

The intensity of a laser beam

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electric field

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magnetism

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a.   mass number from atomic number

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.