Answer:
(a) 2.88×10⁻² W/m²
(b) 8.36×10⁻³ W/m²
Explanation:
The intensity of sound from an isotropic point source, with distance L is given as
I = P/(4πL²) .................................... Equation 1
Where I = intensity of sound, P = Power from the source, L = length, π = pie.
(a)
1.4 m from the source.
I = P/(4πL²)
Given: P = 0.71 W, L = 1.4 m, π = 3.14.
Substitute into equation 1
I = 0.71/(4×3.14×1.4²)
I = 0.71/24.6176
I = 0.0288 W/m².
I = 2.88×10⁻² W/m²
(b) 2.6 m from the source.
Given: P = 0.71 W, L = 2.6 m, π = 3.14
Substitute into equation 1
I = 0.71/(4×3.14×2.6²)
I = 0.71/84.9056
I = 0.00836 W/m²
I = 8.36×10⁻³ W/m²
Answer:

Explanation:
The annual electricity cost is:


Answer:
θ = 10.28º
Explanation:
To find the angle of refraction use the equation of refraction
n₁ sin θ₁ = n₂ sin θ₂
where index 1 is for incident light and index 2 is for refracted light.
sin θ₂ = n₁ / n₂ sin θ
let's calculate
sin = 1 / 1.3 sin 0.23
sin = 0.175
θ= 0.17528 rad
let's reduce to degrees
θ = 0.17528 rad (180ª / pi rad)
θ = 10.28º
Answer:
Seatbelts stop you
Explanation:
Any passengers in the car will also be decelerated to rest if they are strapped to the car by seat belts.
Using the same antenna. Now he doesn't know if it was the antenna that caused the change in reception. so he wasn't only measuring the reception in his house he was measuring it based on different antennas