Answer:
The optimum wavelength = (8.863 × 10⁻⁷) m = 886.3 nm
Explanation:
The light that will generate the photovoltaic energy of 1.4 eV will must have that amount of energy
Energy of light waves is given as
E = hf
h = Planck's constant = (6.626 × 10⁻³⁴) J.s
f = Frequency of the light
The frequency is then further given as
f = (c/λ)
c = speed of light = (3.0 × 10⁸) m/s
λ = wavelength of the light = ?
E = (hc/λ)
λ = (hc/E)
Energy = E = 1.4 eV = 1.4 × 1.602 × 10⁻¹⁹ = (2.2428 × 10⁻¹⁹) J
λ = (6.626 × 10⁻³⁴ × 3.0 × 10⁸)/(2.2428 × 10⁻¹⁹)
λ = (8.863 × 10⁻⁷) m = 886 nm
Hope this Helps!!!
C)
Plasma is the most abundant state of matter in the universe and has the most kinetic energy. It can be found in all the planets of our solar system, the sun, and other stars
Alternating current (AC) flows half the time in one direction and half the time in the other, changing its polarity 120 times per second with 60-hertz current.
Answer:
400 N
Explanation:
By the law of friction,
is the maximum frictional force, 
is the coefficient of friction and 
is the reaction on the refrigerator. On a horizontal surface, the reaction is equal to the weight of the refrigerator.
While not moving, the fricition on the refrigerator is static friction. So, 
This is the maximum frictional force and is more than the applied horizontal force of 400 N. Frictional force cannot be more than the applied force, else it would actually pull the refrigerator backwards (a strange thing, if it were to happen). It is equal to the extent of the applied force because the applied force is not enough to overcome the maximum.
Hence the frictional force is 400 N.
PS: Note that we do not use the coefficient of kinetic friction because applied force could not overcome the static friction.
