Answer:
It takes <em>40 hours</em> to melt the block of ice.
Explanation:
According to the principles of radiation and heat transfer respectively:
<em>ΔQ = I(dt)eAcosθ </em>(I = Solar energy density; dt = time taken; e = emissivity; A = Area of block; θ = angle between the sun ray and the horizontal)
<em>ΔQ = mLf</em> (ΔQ = Heat change; m = mass of ice; Lf = Specific latent heat of fusion of ice)
but m = ρV = ρ.A.<em>d</em>x, therefore, the heat transfer equation can be re-written as:
<em>ΔQ = ρ.A.dx.Lf</em>
Lets equate the radiation equation and the modified heat transfer equation, we have:
<em>ρ.A.dx.Lf = I(dt)eAcosθ</em>
<em>ρ.dx.Lf = I(dt)ecosθ </em>(Striking out the area)
Let's make <em>dt</em> the subject of formula,
dt = ρ.dx.Lf /I.e.cosθ
ρ = Density of ice,
Lf =
e = 0.050
θ = 32 deg. C
Now, let's substitute the terms:
Therefore, the time taken for the ice to completely melt is <em>40 hours</em> (Two significant figures)
Formula for final velocity: Vf= vi+(a*t)
Vi- initial velocity, a=acceleration, t-time
Vf=vi+(at)
Vf= 0+(9.8m/s*2.8s)
Vf= 27.44 m/s
The acceleration of the Earth when dropping something would be 9.8 m/s
Here is an reference that can help you answer problems like these.
Hope this helps and good luck :)
Answer:
Explanation:
We are given that
The separation between parallel plate capacitor=d=0.81 mm=
Area =A=
Dielectric constant k=2.1
Charge on parallel plate capacitor=
We know that
Where
Substitute the values
Hence, the potential difference between the plates =
From diagram 2, only half of the cycles of alternating current can pass from the unknown component.
It has to be a diode because a diode can only allow current flow in one direction in circuits.