A sound wave is a longitudinal wave
If you think about it, irregular galaxies dont really have a describable shape, as you can tell by the name. So B.
Answer:
r₂ = 0.316 m
Explanation:
The sound level is expressed in decibels, therefore let's find the intensity for the new location
β = 10 log
let's write this expression for our case
β₁ = 10 log \frac{I_1}{I_o}
β₂ = 10 log \frac{I_2}{I_o}
β₂ -β₁ = 10 (
)
β₂ - β₁ = 10
log \frac{I_2}{I_1} =
= 3
= 10³
I₂ = 10³ I₁
having the relationship between the intensities, we can use the definition of intensity which is the power per unit area
I = P / A
P = I A
the area is of a sphere
A = 4π r²
the power of the sound does not change, so we can write it for the two points
P = I₁ A₁ = I₂ A₂
I₁ r₁² = I₂ r₂²
we substitute the ratio of intensities
I₁ r₁² = (10³ I₁ ) r₂²
r₁² = 10³ r₂²
r₂ = r₁ / √10³
we calculate
r₂ =
r₂ = 0.316 m
A has less energy and lower frequency, while B has greater energy and higher frequency.
Answer:
i/f = i/o + i/i f = focal, o = object, i = image
1 / i = 1 / f - 1 / o = (o - f) / o f
i = o * f / ( o - f) image distance
i = 12.5 * 22 / (12.5 - 22) = -28.9 cm
Image is real
Image is 28.9 cm to left of lens
M = - i / o = = 28.9 / 12.5 = 2.3 magnification (convex lens)