A certain sound source is increased in sound level by 21 dB. By what multiple is (a) its intensity increased and (b) its pressure amplitude increased?

(a). The Final intensity is 126 times of initial intensity.

(b). The pressure amplitude increased is 11.22 times of initial pressure.

Explanation:

Given that,

Sound level = 21 dB

(a). We need to calculate the increases increases

Using sound level equation

The intensity level for original sound level is

The intensity level for final sound level is

Subtract equation (I) from equation (2)...

Put the value into the formula

The Final intensity is 126 times of initial intensity.

(b). We need to calculate the pressure amplitude increased

Using formula of pressure

The pressure amplitude increased is 11.22 times of initial pressure.

Hence, (a). The Final intensity is 126 times of initial intensity.

(b). The final pressure amplitude is 11.22 times of initial pressure.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

it was given as a lesson and guide for prayer.