Explain that resistance is dependent on temperature in thermistor.

This diagram shows a potential divider.

What happens when the temperature decreases?

(A) The resistance of the thermistor decreases and $V_{\text{out }}$ decreases.

(B) The resistance of the thermistor decreases and $V_{\text{out }}$ increases.

(C) The resistance of the thermistor increases and $V_{\text{out }}$ decreases.

(D) The resistance of the thermistor increases and $V_{\text{out }}$ increases.

The circuit shown in Figure produces a decreasing output voltage when the light intensity increases. How can the circuit be altered to produce an increasing output voltage as the light intensity increases?

An LDR used as a sensor.

Determine the range of $V_{\text{out }}$ for the circuit in Figure as the variable resistor $R_2$ is adjusted over its full range from $0\Omega$ to $40\Omega$. (Assume the supply of e.m.f. $10 \mathrm{V}$ has negligible internal resistance.)

What is the voltage across the $3.0\mathrm{k}\Omega$ resistor in Figure when the light intensity is 10 lux?

This diagram shows two circuits that could be used to act as a dimmer switch for a lamp.

(b) (i) The lamp is rated at $60 \mathrm{W}$ at $240 \mathrm{V}$. Calculate the resistance of the lamp filament at its normal operating temperature.

This diagram shows two circuits that could be used to act as a dimmer switch for a lamp.

(a) Explain one advantage circuit 1 has over circuit $2$.

This diagram shows two circuits that could be used to act as a dimmer switch for a lamp.

State and explain how the resistance of the filament at room temperature would compare with the value $960\Omega$.

This circuit shows a potential divider. The battery has negligible internal  resistance and the voltmeter has infinite resistance.

(a) State and explain how the reading on the voltmeter will change when the resistance of the variable resistor is increased.

This circuit shows a potential divider. The battery has negligible internal  resistance and the voltmeter has infinite resistance.

Resistor ${\mathrm{R}}_2$ has a resistance of $470\mathrm{\Omega }$. Calculate the value of the variable resistor when the reading on the voltmeter is $2.0\mathrm{V}$.

This circuit shows a potential divider. The battery has negligible internal  resistance and the voltmeter has infinite resistance.

The voltmeter is now replaced with one of resistance $2\mathrm{k\Omega }$. Calculate the reading on this voltmeter.