An electrical device needs a voltage of $5.0\,\text{V}$ to function normally. The mains supply voltage is $250\,\text{V}$. Which row shows a transformer that gives an output voltage allowing the device to work normally when it is connected to the mains supply?
- Anumber of turns on the primary coil $= 500$, number of turns on the secondary coil $= 2500$
- Bnumber of turns on the primary coil $= 500$, number of turns on the secondary coil $= 25000$
- Cnumber of turns on the primary coil $= 2500$, number of turns on the secondary coil $= 500$
- Dnumber of turns on the primary coil $= 25000$, number of turns on the secondary coil $= 500$