Answer:
L = 130 decibels
Explanation:
The computation of the sound intensity level in decibels is shown below:
According to the question, data provided is as follows
I = sound intensity = 10 W/m^2
I0 = reference level = 
Now
Intensity level ( or Loudness)is




Therefore
L = 13 bel
And as we know that
1 bel = 10 decibels
So,
The Sound intensity level is
L = 130 decibels
D. Light from the sun is reflected off the moon's surface
Explanation:
It is given that,
Mass of an electron, 
Initial speed of the electron, 
Final speed of the electron, 
Distance, d = 5 cm = 0.05 m
(a) The acceleration of the electron is calculated using the third equation of motion as :



Force exerted on the electron is given by :



(b) Let W is the weight of the electron. It can be calculated as :



Comparison,


Hence, this is the required solution.
Answer:
λ = 8.88 x 10⁻⁷ m = 888 nm
Explanation:
The energy band gap is given as:
Energy Gap = E = 1.4 eV
Converting this to Joules (J)
E = (1.4 eV)(1.6 x 10⁻¹⁹ J/1 eV)
E = 2.24 x 10⁻¹⁹ J
The energy required for photovoltaic generation is given as:
E = hc/λ
where,
h = Plank's Constant = 6.63 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of light = ?
Therefore,
2.24 x 10⁻¹⁹ J = (6.63 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/λ
λ = (6.63 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(2.24 x 10⁻¹⁹ J)
<u>λ = 8.88 x 10⁻⁷ m = 888 nm</u>
That is b. hope this helps cx