Answer:
a
b
Explanation:
From the question we are told that
The wavelength is 
The energy is 
This energy is mathematically represented as
Where c is the speed of light with a value 
h is the Planck's constant with the value 
n is the number of pulses
So
substituting values
Given that the pulses where emitted 20 times in one second then the period of the pulse is
Hence the average power of photons in one 80-mJ pulse during 1 s is mathematically represented as
substituting values
Answer:
(e) thermal expansion
Explanation:
The density, the heat of fusion and the melting temperature of the metal are determining characteristics to take into account to raise the temperature of the metal from room temperature to the melting temperature. Since they will determine the following:
Density: is the relationship between the mass of a body and the volume it occupies in outer space.
Heat of fusion: The enthalpy of fusion or heat of fusion is the amount of energy needed to make a mole of an element that is at its melting point pass from the solid state to the liquid, at constant pressure.
Melting temperature is defined as the temperature at which the phase transition from the solid state to the liquid occurs at normal atmospheric pressure.
While the dilution of metals will only have an influence on the volume it will occupy but not on the heating process
C. Mechanical, because temperature can cause solid objects to expand and contract, causing rocks to split apart.
Answer:
D. Electricity will flow if the electrons are bound loosely to their atoms in the material.
Explanation:
The continuous flow of charges is known as electricity (current). The flow of these charges are due to free or mobile electron within the atoms of the conductors. The materials which will allow current to pass through them, must have free or mobile electrons which are loosely bound to their atoms.
Thus, the correction for this question is "D"
D. Electricity will flow if the electrons are bound loosely to their atoms in the material.
The answer is C..........
