<h2>
Answer:</h2>
1000th multiple of the standard reference level for intensities.
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Explanation:</h2>
The sound intensity level (β), measured in decibels, of a sound with an intensity of I is defined as follows;
β = 10 log (I / I₀) --------------------(i)
Where;
I₀ = reference intensity
Given from the question;
β = sound level = 30dB
Substitute this value into equation (i) as follows;
30 = 10 log (I / I₀)
Divide both sides by 3;
3 = log (I / I₀)
Take antilog of both sides;
10^(3) = (I / I₀)
1000 = I / I₀
Solve for I;
I = 1000I₀
Therefore the intensity of the sound is 1000 times the standard reference level for intensities (I₀)
Answer;
the potential difference
The magnitude of the electric current is directly proportional to the potential difference of the electric field
Explanation;
An electric current results from the collective movement of free charges under the effect of an electric field. An electric field exists and can be observed in the space around a single charge or a number of charges.
Electric fields cause charges to move. It stands to reason that an electric field applied to some material will cause currents to flow in that material. In other words, the current density is directly proportional to the electric field. The constant of proportionality σ is called the material’s conductivity.
Answer:
Constructive Interference
Explanation:
Constructive Interference occurs when two waves superimpose and make bigger amplitudes.
In constructive interference, the crests of one wave fall on the crests of second wave and the amplitudes add up. The amplitude of the resultant wave is equal to sum of the amplitude of the individual waves. Similarly, the trough of first wave falls on the trough of other wave and they superimpose to create the trough of the resultant wave.
For Example, In the attachment, two waves A and B superimpose and demonstrate Constructive interference to create the wave C.
Answer:
157.9 kg
Explanation:
Density: This can be defined as the ratio of the mass of a body and it's volume.
The S.I unit of density is kg/m³.
From the question,
Density = Mass/volume
D = m/v............................ Equation 1
Where D = Density of gold, m = mass of gold, v = volume of gold.
make m the subject of the equation
m = Dv.................... Equation 2
Since the gold is a cube,
v = l³................... Equation 3
Where l = length of the gold cube.
Substitute equation 3 into equation 2
m = Dl³............... Equation 4
Given: D = 19300 kg/m³, l = 0.2015 m
Substitute into equation 4
m = 19300(0.2015)³
m = 157.9 kg.
Scientific evidence supports a new idea
