(a(i))[1]
State the energy form stored in the battery.
(a(ii))[1]
State the useful output energy form from the battery.
(a(iii))[2]
State two useful output energy forms from the mobile phone.
(b)[2]
The battery is operating with an average current of $1.3\,\text{mA}$. Determine the charge that flows through the battery in a time of $2.0\,\text{minutes}$.
(c(i))[3]
Calculate the thermal energy needed to increase the battery temperature by $5.0\,^\circ\text{C}$.
(c(ii))[2]
State what efficiency means.
(c(iii))[2]
Calculate the efficiency of the battery.
(c(iv))[2]
Suggest and explain one reason why the efficiency calculated in (iii) is greater than the battery's actual efficiency.