closed and unsecure circuit
Answer:
β = 114 db
Explanation:
The intensity of sound in decibles is
β = 10 log 
in most cases Io is the hearing threshold 1 10-12 W / cm²
let's calculate the intensity of each instrument
I / I₀ = 10 (β / 10)
I = I₀ 10 (β / 10)
trumpet
I1 = 1 10⁻¹² 10 (94/10)
I1 = 2.51 10⁻³ / cm²
Thrombus
I2 = 1 10⁻¹² 10 (107/10)
I2 = 5.01 10-2 W / cm²
low
I3 =1 1-12 (113/10) W/cm²
I3 = 1,995 10-1 W / cm²
when we place the three instruments together their sounds reinforce
I_total = I₁ + I₂ + I₃
I_ttoal = 2.51 10-3 + 5.01 10-2 + 1.995 10-1
I_total = 0.00251 + 0.0501 + 0.1995
I_total = 0.25211 W / cm²
let's bring this amount to the SI system
β = 10 log (0.25211 / 1 10⁻¹²)
β = 114 db
Answer:
The new potential energy decreases by the factor of 2 to the old potential energy.
Explanation:
Capacitance of a parallel plate capacitor is given by the relation :
C = (ε₀A)/d
Here ε₀ is vacuum permittivity, A is area of the capacitor plate and d is the distance between them.
Potential energy of the capacitor, U = 
Here V is the potential difference between the plates.
According to the problem, the distance between the plates get double but area remains same. So,
d₁ = 2d
Here d₁ is new distance between the plates.
Hence, new capacitance is :
C₁ = (ε₀A)/d₁ = (ε₀A)/2d = C/2
The capacitor have same potential difference that is V. Hence, the new potential energy is :
U₁ =
= 
U₁ = U/2
