Answer:
Microwave: Radiation
Water: Conduction, convection & radiation.
Explanation:
- When we heat a food using microwave then the water content of the food is only heated by the microwave.
- Microwaves make the molecules of water vibrate frequently with a frequency closer to the frequency of microwaves and this increases the kinetic energy of the molecules which produces heat in the water molecules this heat then propagates to the whole food by conduction and convection, but the heat enters the food only via radiation.
Now when the food item is kept into warm water then the molecules closer to the food heat the food by conduction through direct energy transfer by lattice vibrations and when they become cooler than the mass of water all around then due to density difference they settle down and their place is occupied by warmer molecules around in the fluid leading to convection.
Radiation of energy from a mass occurs continuously irrespective of the medium present there. So the heat of water also enters the food by radiation of energy from the water molecules.
The available options are:
A. bartenders serving alcohol
B. students identifying their professors.
C. Doctors diagnosing cases of schizophrenia.
D. eyewitnesses identifying suspects from a lineup.
Answer:
A. bartenders serving alcohol
Explanation:
This is because of the underage rule concerning sale of alcohol. Thus, there are occasional period in which underage person or a minor will want to buy alcohol, and without necessarily asking for the birth certificate or ID card that contains Age information, it is therefore, necessary for bartenders to be able to tell the age of their unfamiliar customers, by mere looking at them, so as not to sell to a minor.
Hemce, Rhodes research in guessing the age of unfamiliar person has important implications for BARTENDERS SERVING ALCOHOL, because it will guide them to determine Underage or Minor, that want to buy alcohol from them.
The magnet is at a gravitational force while the paper clip is at an applied force
Answer:
A) U₀ = ϵ₀AV²/2d
B) U₁ = (ϵ₀AV²)/6d
This means that the new energy of the capacitor is (1/3) of the initial energy before the increased separation.
C) U₂ = (kϵ₀AV²)/2d
Explanation:
A) The energy stored in a capacitor is given by (1/2) (CV²)
Energy in the capacitor initially
U₀ = CV²/2
V = voltage across the plates of the capacitor
C = capacitance of the capacitor
But the capacitance of a capacitor depends on the geometry of the capacitor is given by
C = ϵA/d
ϵ = Absolute permissivity of the dielectric material
ϵ = kϵ₀
where k = dielectric constant
ϵ₀ = permissivity of free space/air/vacuum
A = Cross sectional Area of the capacitor
d = separation between the capacitor
If air/vacuum/free space are the dielectric constants,
So, k = 1 and ϵ = ϵ₀
U₀ = CV²/2
Substituting for C
U₀ = ϵ₀AV²/2d
B) Now, for U₁, the new distance between plates, d₁ = 3d
U₁ = ϵ₀AV²/2d₁
U₁ = ϵ₀AV²/(2(3d))
U₁ = (ϵ₀AV²)/6d
This means that the new energy of the capacitor is (1/3) of the initial energy before the increased separation.
C) U₂ = CV²/2
Substituting for C
U₂ = ϵAV²/2d
The dielectric material has a dielectric constant of k
ϵ = kϵ₀
U₂ = (kϵ₀AV²)/2d
Conductive current is the answer I d k