(a)[2]
State two characteristics of an ideal operational amplifier (op-amp).
(b)[1]
Fig. 7.1 shows a circuit containing an ideal op-amp and two identical resistors $R$. State the names of components $X$ and $Y$.
(c(i))[2]
Explain why the op-amp in Fig. 7.1 has just two possible output states.
(c(ii))[1]
State the name of the op-amp circuit type in which the op-amp behaves as in (c)(i).
(c(iii))[2]
Describe the environmental condition that makes the lamp $L$ in Fig. 7.1 light up.
(c(iv))[1]
Suggest the role of the variable resistor $V$ in the circuit.
(iii)[2]
Describe the environmental condition that causes lamp $L$ in Fig. 7.1 to light.
(iv)[1]
Suggest the role of the variable resistor $V$ in the circuit.