The white disks in the petri plates are soaked in herbicide, which affects the roots, stalks, leaves, and cobs of a corn plant.
1 answer:
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Answer:
The distance is
Explanation:
From the question we are told that
The distance from the conversation is
The intensity of the sound at your position is
The intensity at the sound at the new position is
Generally the intensity in decibel is is mathematically represented as
The intensity is also mathematically represented as
So
=>
From the logarithm definition
=>
=>
Here P is the power of the sound wave
and A is the cross-sectional area of the sound wave which is generally in spherical form
Now the power of the sound wave at the first position is mathematically represented as
Now the power of the sound wave at the second position is mathematically represented as
Generally power of the wave is constant at both positions so
substituting value
Answer:
f =-20 cm
Explanation:
Given that,
The magnification of a spherical mirror, m = -1
The image distance, v = 40 cm (for negative magnification)
The magnification of a concave mirror is negative. The mirror showing -1 magnification is a concave mirror.
Let f be the focal length of the mirror. We know that,
Object distance, u = -40 cm
Using mirror's formula i.e.
So, the focal length of the mirror is 20 cm.