Answer:
iv) It is 9x bigger than before
Explanation:
As the amplitudes of the new speakers add directly with the original one, taking into account the phase that they have, the composed amplitude of the sound wave is as follows:
At = A + 4A -2A = 3 A
The intensity of the wave, assuming it propagates evenly in all directions, is constant at a given distance from the source, and can be expressed as follows:
I = P/A
where P= Power of the wave source, A= Area (for a point source, is equal to the surface area of a sphere of radius r, where is r is the distance to the source along a straight line)
For a sinusoidal wave, the power is proportional to the square of the amplitude, so the intensity is proportional to the square of the amplitude also.
If the amplitude changes increasing three times, the change in intensity will be proportional to the square of the change in amplitude, i.e., it will be 9 times bigger.
So, the statement iv) is the right one.
Pure substances can be elements made up exclusively of one kind of atom, or they can be compounds made up of molecules that include two or more elements. Mixtures can be homogeneous or heterogeneous depending on how finely mixed the components are.
Answer:increased
Explanation:
It is given that elevator speed is increasing while moving upward i.e.its acceleration is increasing .
This causes the apparent to be increased if measured using weighing machine.
considering upward direction to be positive
N-mg=ma
N=m(g+a)
where N=Normal reaction=Apparent weight
a=acceleration of Elevator
thus you feel as if your weight is increased.
Two neutral objects will not have any electric force of attraction or repulsion between them.
<h3>What is the condition for the electric force between two objects?</h3>
As we know from the electrostatics that whenever there are two charges having a positive charge on one and a negative on the other will attract each other
similarly, if they are having like charges which are both of them having positive or both of them having a negative charge then there will be a force of repulsion between them.
But if both of them or even one of them is neutral then there will not be any electric force between them.
Thus neutral objects will not have any electric force of attraction or repulsion between them.
To know more about the nature of charged particles follow
brainly.com/question/22492496