Answer:
A blackbody, or Planckian radiator, is a cavity within a heated material from which heat cannot escape. No matter what the material, the walls of the cavity exhibit a characteristic spectral emission, which is a function of its temperature.
Example:
Emission from a blackbody is temperature dependent and at high temperature, a blackbody will emit a spectrum of photon energies that span the visible range, and therefore it will appear white. The Sun is an example of a high-temperature blackbody.
Answer:
- No, this doesn't mean the electric potential equals zero.
Explanation:
In electrostatics, the electric field 
is related to the gradient of the electric potential V with :
This means that for constant electric potential the electric field must be zero:
This is not the only case in which we would find an zero electric field, as, any scalar field with gradient zero will give an zero electric field. For example:
give an electric field of zero at point (0,0,0)
The answer is: Expressive vocabulary
Expressive vocabulary refers to the combination of all the words that a person has acquire throughout his/her life and can be used in various type of situations.
This would include all words in the child vocabulary, starting from the child's written language, spoken language or even the child's manually signed words.
The car has a 12 mile head start, going 80 mph, so his distance is:dcar=80∗t+12
The is going at 108 mph, so his distance is:dcop=108t
Setting them equal to each other we get:80t+12=108t⇒12=28t⇒t=1228=37
So 3/7 of an hour.about 25.7 mins.
