2.12 describe the qualitative variation of resistance of LDRs with illumination and of thermistors with temperature

LDR (light dependent resistor) changes the intensity of light:

• The brighter the light, the more resistance
• The dimmer the light, the less resistance

Thermistor are used as temperature sensors (e.g. fire alarms):

• The higher the temperature, the less resistance
  
• The lower the temperature, the more resistance