Figure 1 shows a circuit designed by a student to monitor changes in light intensity.
The supply has negligible internal resistance and the light-dependent resistor (LDR) has a resistance of 1500 Ω at a baseline light level. The student wants the output potential difference (VoutV_{\text{out}}Vout) at this light level to be 10.0 V.
The 0.50 kΩ0.50\text{ k}\Omega0.50 kΩ resistor is made of 120 turns of wire that is wound around a non-conducting cylinder of diameter 4.0 mm. Resistivity of the wire = 4.5 × 10-7 Ω m. Determine the area of cross-section of the wire that has been used for the resistor.
The student selects a resistor rated at 0.60 W for the 0.50 kΩ0.50\text{ k}\Omega0.50 kΩ resistor. Determine whether this resistor is suitable.
Determine the value of R R\,R that the student should select. Give your answer to an appropriate number of significant figures.
State and explain the effect on the output pd (VoutV_{\text{out}}Vout) of increasing the light intensity incident on the LDR.