Current, potential difference and resistanceIB MYP Sciences: Mind map

Exam questions on Current, potential difference and resistance

1. A technician in Nairobi is testing a small solar-powered lamp. A steady current of 0.50 A flows through the lamp for 2.0 minutes.
   State where an ammeter and a voltmeter should be connected to measure the current through the lamp and the potential difference across it.2 marks
2. A student in Seoul connects a fixed resistor to a 6.0 V battery and measures a current of 0.20 A through the resistor.
   The student replaces the resistor with one of twice the resistance and keeps the same battery. Calculate the new current.2 marks
3. A greenhouse controller in Almería, Spain, uses a thermistor to monitor the air temperature and a light-dependent resistor (LDR) to monitor daylight. Each sensor is connected to a constant 3.0 V supply.
   Describe how the resistance of the thermistor changes as the greenhouse warms up, explain the effect on the current in its circuit, and suggest how the controller could use this change.3 marks