Answer:
best explanation of this is sentence B
Explanation:
The radiation emission of the bodies is given by the expression
P = σ A e T⁴
Where P is the power emitted in watts, σ is the Stefan-Boltzmann constant, A is the surface area of the body, e is the emissivity for black body e = 1 and T is the absolute body temperature in degrees Kelvin.
When the values are substituted the power is quite high 2.5 KW, but the medium surrounding the box also emits radiation
T box ≈ T room
P box ≈ P room
As the two powers are similar and the box can absorbed, since it has the ability to emit and absorb radiation, as the medium is also close of the temperature of the box, the amount emitted is very similar to that absorbed, so the net change in energy is very small.
In the case that the box is much hotter or colder than the surrounding medium if there is a significant net transfer.
Consequently, the best explanation of this is sentence B
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!!!
Answer:
Negative
Explanation:
First law of thermodynamic also known as the law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed.
The first law relates relates changes in internal energy to heat added to a system and the work done by a system by the conservation of energy.
The first law is mathematically given as ΔU =
-
= Q - W
Where Q = Quantity of heat
W = Work done
From the first law The internal energy has the symbol U. Q is positive if heat is added to the system, and negative if heat is removed; W is positive if work is done by the system, and negative if work is done on the system.
Analyzing the pistol when it raises in isothermal and when it falls in isobaric state.The following can be said:
In the Isothermal compression of a gas there is work done on the system to decrease the volume and increase the pressure. For work to be done on the system it is a negative work done then.
In the Isobaric State An isobaric process occurs at constant pressure. Since the pressure is constant, the force exerted is constant and the work done is given as PΔV.If a gas is to expand at a constant pressure, heat should be transferred into the system at a certain rate.Isobaric is a fuction of heat which is Isothermal Provided the pressure is kept constant.
In Isobaric definition above it can be seen that " Heat should be transferred into the system ata certain rate. For heat to be transferred into the system work is deinitely been done on the system thereby favouring the negative work done.
Before you step on the brakes, the car has kinetic energy, when you step on the brakes, it turns the kinetic energy into heat (thermal energy). When it stops completely, it has potential energy. Hope this helped :)