(a(i))[1]
On Fig. 9.1, mark the virtual earth with the letter X.
(a(ii))[3]
Explain the meaning of the term virtual earth.
(b(i))[3]
In bright sunlight, the light-dependent resistor (LDR) has a resistance of $200\,\Omega$. Calculate the voltmeter reading for the LDR in bright sunlight.
(b(ii))[3]
The sunlight incident on the LDR becomes less bright. State and explain the effect on the voltmeter reading caused by this drop in brightness.