Answer:
n = 2.208x10¹⁸ photons
Explanation:
The energy of a photon( an elementary particle) is given by the equation:
E = nxhxf
Where n is the number of photons, h is plank constant (6,62x10⁻³⁴ J.s), and f is the frequency. Knowing that the power level is 0.120mW (1.2x10⁻⁴ W), the energy in J, for a time of 78 min (4680 s)
E = 1.2x10⁻⁴x4680 = 0.5616 J
The frequency of a photon is its velocity ( c= 3x10⁸ m/s) divided by its wavelength, which is 780 nm = 780x10⁻⁹ m
f = 3x10⁸/780x10⁻⁹
f = 3.846x10¹⁴ s⁻¹
Then, the number of photons is:
0.5616 = nx6,62x10⁻³⁴x3.846x10¹⁴
n = 2.208x10¹⁸ photons.
Answer : The balanced two-half reactions will be,
Oxidation half reaction : 
Reduction half reaction : 
Explanation :
Voltaic cell : It is defined as a device which is used for the conversion of the chemical energy produces in a redox reaction into the electrical energy. It is also known as the galvanic cell or electrochemical cell.
In the voltaic cell, the oxidation occurs at an anode which is a negative electrode and the reduction occurs at the cathode which is a positive electrode.
The given redox reaction is:
The balanced two-half reactions will be,
Oxidation half reaction :
Reduction half reaction :
Cross contamination can be caused by CARRYING DRINKING GLASSES BY THE RIMS.
Cross contamination refers to the transfer of harmful microbes to foods from various sources. The rim of a drinking glass is where you put your mouth when you are drinking from a glass cup. If one is carrying a drinking glass by the rim, one can easily transfer the dirty in one's hand to the glass and this will be ingested by person who use the cup. Drinking glasses should be carried by holding their bases.
