Answer:
The intensity level in the room is 63 dB
Explanation:
To calculate the intensity of sound in the room, we use the equation of definition of decibels
β = 10 log (I / Io) (1)
With “I” the sound intensity and “Io” the threshold intensity 1.0 10⁻⁻¹² W/m²
To calculate the intensity we will use the initial data and remember the power of the emitted sound is constant, in addition that the sound propagates in three-dimensional form or on a spherical surface
I = P/A ⇒ P = I A
The area of a sphere is 4 π r², where I can calculate of 1
β/10 = log (I/Io)
I / Io = 
I = Io
I = 1 10⁻¹² 10⁽¹⁰⁰/¹⁰⁾ = 1 10⁻¹² 10¹⁰
I = 1.0 10⁻² W
With this we can calculate the intensity for a distance of 20 m
I = 1.0 10⁻² / ( 4π 20²)
I = 2.0 10⁻⁶ W/m²
We have already found the intensity at the point of interest, so we can calculate the intensity in decibels at this point with equation 1
β = 10 log(2.0 10⁻⁶ / 1.0 10⁻¹²)
β = 10 log ( 2 10⁶) = 10 6.3
β = 63 dB
The intensity level in the room is 63 dB
Answer:
The focal length of eye piece is 6.52 cm.
Explanation:
Given that,
Angular Magnification of the microscope M = -46
the distance between the lens in microscope L= 16 cm
The focal length of objective f₀ = 1.5 cm
Normal near point N = 25 cm
Have to find focal length of eye piece f ₙ =?
The angular magnification is given by
M ≈ - (L-fₙ)N/f₀fₙ
Rearranging for fₙ
fₙ =L(1 - Mf₀/N)⁺¹
=18/2.76
fₙ = 6.52 cm
The focal length of eye piece is 6.52 cm.
Answer:
See the explanation below
Explanation:
We must perform a sum of forces on the body, that sum of forces is equal to zero. That is, the body is in balance and does not move.
ΣF = 0
3 - 3 = 0
This force is negative and acts by pointing downwards.
Answer:
true
Explanation:
The law of conservation of mass states that in a chemical reaction mass is neither created nor destroyed. For example, the carbon atom in coal becomes carbon dioxide when it is burned. The carbon atom changes from a solid structure to a gas but its mass does not change.
Answer:
Tarzan will be moving at 7.4 m/s.
Explanation:
From the question given above, the following data were obtained:
Height (h) of cliff = 2.8 m
Initial velocity (u) = 0 m/s
Final velocity (v) =?
NOTE: Acceleration due to gravity (g) = 9.8 m/s²
Finally, we shall determine how fast (i.e final velocity) Tarzan will be moving at the bottom. This can be obtained as follow:
v² = u² + 2gh
v² = 0² + (2 × 9.8 × 2.8)
v² = 0 + 54.88
v² = 54.88
Take the square root of both side
v = √54.88
v = 7.4 m/s
Therefore, Tarzan will be moving at 7.4 m/s at the bottom.
