Which of these could be the output for a dynamo? A B C D (i) Figure 17 shows the output from a battery - Edexcel - GCSE Physics - Question 9 - 2018 - Paper 1

To find the potential difference across the secondary coil, we can use the transformer equation:

$\frac{V_s}{V_p} = \frac{N_s}{N_p}$

Where:

• $V_s$ = potential difference across the secondary coil
• $V_p$ = potential difference across the primary coil (25 V)
• $N_s$ = number of turns on the secondary coil (150)
• $N_p$ = number of turns on the primary coil (30)

Substituting the values:

$\frac{V_s}{25} = \frac{150}{30}$

Rearranging gives:

$V_s = 25 \times \frac{150}{30}$

Calculating:

$V_s = 25 \times 5 = 125 V$

Therefore, the potential difference across the secondary coil is 125 V.

High voltage transmission is essential for reducing energy loss in power distribution. When electrical power is transmitted over long distances, resistance in the cables causes power loss in the form of heat, given by the formula:

$P = I^2R$

Where:

• $P$ = power loss
• $I$ = current
• $R$ = resistance of the cables

By using transformers, the voltage can be increased at the transmission stage, reducing the current needed for the same power level. This means:

• Higher voltage results in lower current, leading to significantly reduced power loss.
• As a result, consumer voltage can be stepped down safely using transformers, ensuring safety and efficiency.

Overall, this method allows electricity to be transmitted over long distances with minimal energy wastage, maintaining an efficient power distribution system.