(a)[2]
State Faraday’s law for electromagnetic induction.
(b)
An ideal transformer is linked to a bridge rectifier, as shown in Fig. $6.1$. The transformer input is $240\,\text{V r.m.s.}$ and the highest potential difference across the load resistor is $9.0\,\text{V}$.
(b(i))[1]
On Fig. $6.1$, put the letter P at the rectifier’s positive output.
(b(ii))[3]
Calculate the ratio $\dfrac{\text{turns in the primary coil}}{\text{turns in the secondary coil}}$.
(c)
The change of potential difference $V$ across the load resistor in (b) with time $t$ is shown in Fig. $6.2$. A capacitor is then connected in parallel with the load resistor to give some smoothing.
(c(i))[1]
Explain what smoothing means.
(c(ii))[2]
On Fig. $6.2$, sketch how the smoothed output potential difference changes with time $t$.