Watchglass is a lab equipment that is used as a cover to prevent heated materials from splattering out of the container and as a holding plate for hot or flammable materials
<u>Explanation:</u>
Watch glass is an equipment used as a cover to prevent heated materials from splattering out of the container and as a holding plate for hot or flammable materials. It is a kind of concave glass which is also used to evaporate a liquid and also provides good air circulation which is used during cooking. The name watchglass was derived as they are see through and so similar to pocket glasses.
Placing elements into columns, groups, rows and periods that share certain properties. properties such as gas, solid and liquid determine an element physical state at room temperature.
I think these gases are water vapor and nitrogen. As the temperature rises, these water vapor molecules, would condense and form the oceans we have. Also, it was said that in the early atmosphere, nitrogen is very abundant and even today the composition of air is 79% by volume.
In thinking about inherited traits, geneticists use two important words: genotype and phenotype. Genotype refers to the genes an organism inherits from its parents and phenotype refers to the observable characteristics of an organism: how it develops, looks, reacts and behaves. An inherited trait refers to a phenotypic characteristic, for example flower color, length of gestation or ability to metabolize cellulose. All traits have a genetic basis.
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