A light or optical microscope most commonly uused is a
1 answer:
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Answer:
.
Explanation:
Based on the electron configuration of this ion, count the number of electrons in this ion in total:
.
Each electron has a charge of .
Atoms are neutral and have charge. However, when an atom gains one extra electron, it becomes an ion with a charge of
. Likewise, when that ion gains another electron, the charge on this ion would become
.
The ion in this question has a charge of . In other words, this ion is formed after its corresponding atom gains two extra electrons. This ion has
electrons in total. Therefore, the atom would have initially contained
electrons. The atomic number of this atom would be
.
Refer to a modern copy of the periodic table. The element with an atomic number of is sulphur with atomic symbol
. To denote the ion, place the charge written backwards ("
" for a charge of
) as the superscript of the atomic symbol:
.
(a) Power of bulb is 100 W, converting this into kW.
Thus,
The bulb is used for 6 hours per day for a year, in 1 year there are 365 days thus, total hours will be:
Electricity used will depend on power and number of hours as follows:
The cost of electricity is $0.15 per kW.h thus, cost of electricity for 219 kW.h will be:
Therefore, annual cost of incandescent light bulb is
(b) Power of bulb is 25 W, converting this into kW.
Thus,
The bulb is used for 6 hours per day for a year, in 1 year there are 365 days thus, total hours will be:
Electricity used will depend on power and number of hours as follows:
The cost of electricity is $0.15 per kW.h thus, cost of electricity for 54.75 kW.h will be:
Therefore, annual cost of fluorescent bulb is .