67.8 turns needed by the secondary coil to run the bulb.
<u>Explanation</u>:
We know that,



For calculating number of turns

Given that,



We need to find the number of turns in the secondary winding
to run the bulb at 120W 
Firstly find the secondary voltage in the transformer use, 






Now, finding the number of turns in secondary coil. Use, 




The number of turns in the secondary winding are 67.8 turns.
Atomic number=Proton count
Atomic mass=Proton count+ neutron count
Neuton Count=Atomic mass-Proton count
Proton count=Atomic number=27
Mass number=74
Neuton count= 74-27=47
Answer:
25000 V
Explanation:
The formula for potential is
V = Kq/r
Potential at B due to the charge placed at origin O
V1 = K q / OB

V1 = 10000 V
Potential at B due to the charge placed at A
V2 = K q / AB

V2 = 15000 V
Total potential at B
V = V1 + V2 = 10000 + 15000 = 25000 V
As I found out the choices for your question which are:
<span>A) F2 to F-
B) Cr2O7²- → Cr2+
C) O2 to H2O
D) HAsO2 to As
</span>
Unfortunately, the answer does not belong to the choices provided. In fact, it is the oxidation half-reaction that occurs at the anode of an electrode for it to transform chemical energy to consumable electrical energy.