Hypothesis
As the intensity of light falling on a beaker increases, the
resistance of the LDR decreases.
Equipment
- Light dependent resistor (LDR)
- Leads
- Multimeter
- Bench lamp
- Metre rule
Method
Connect up the LDR to the multimeter. The multimeter should
be set to measure resistance. Place the bench lamp so that it is 1m away from
the LDR (use the metre rule to measure this). Turn on the bench lamp and record
the resistance of the LDR. Move the lamp 10cm closer (to 90cm) and repeat the
process. Continue this until the lamp is 10cm from the LDR
Variables
Independent Variable: Distance between lamp and LDR (or
light intensity)
Dependent variable: Resistance of LDR
Control Variables: Type of LDR, resistance of connecting
leads, brightness of lamp
Risk Assessment
This is a low risk experiment but care must be taken to
avoid burns from the bench lamp. To minimise this risk, ensure that the lamp is
turned off in between readings.