Aparticular person's eardrum is circular, with a diameter of 7.90 mm. how much sound energy (in j) is delivered to an eardrum in one second, at the threshold of human hearing? (the threshold of human hearing is taken to be 1.00 ✕ 10−12 w/m2.)

The sound energy is .

Explanation:

Given that,

Diameter = 7.90 mm

Suppose the intensity for threshold of pain is 1.00 W/m².

We need to calculate the area

Formula of area

Put the value into the formula

We need to calculate the power

Using formula of power

Where, P = Power

I = intensity

A = area

Put the value into the formula

We need to calculate the incident power at the threshold of pain

Using formula of power

We need to calculate the energy

Using formula of energy

Where. P = power

t = time

Put the value into the formula

Hence, The sound energy is .

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz

close lines strong magnet less close weaker