# P2 Topic 2

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### The students found this information relating output current and light intensity (brightness) for a solar cell. The difference in output current between medium light intensity and high light intensity is • A. 5 mA
• B. 10 mA
• C. 15 mA
• D. 25 mA

### The current in a lamp is measured by connecting

• A. An ammeter in series with the lamp.
• B. An ammeter in parallel with the lamp.
• C. A voltmeter in series with the lamp.
• D. A voltmeter in parallel with the lamp.

### The lamps used in these four circuits are identical. Which circuit has the biggest current? • A.
• B.
• C.
• D.

### Some students are investigating how current varies with voltage for a resistor. Which circuit should they use? • A.
• B.
• C.
• D.

### From the previous question, the students plot this graph. Remember V = I x R. What is the resistance at 4V ? • A. 0.08 Ohms
• B. 0.32 Ohms
• C.0.5 Ohms
• D. 50 Ohms

### The graph shows that between 0 and 6 volts the resistance of the resistor is

• B. Constant
• C. A maximum at 6 V
• D. Proportional to current

### Some students are investigating sensors. They find this information about a thermistor. When the temperature increases from 10 deg C to 50 deg C, the resistance will • A. Decrease by about 14 Ohms
• B. Decrease by about 18 Ohms
• C. Decrease by about 14 000 Ohms
• D. Decrease by about 18 000 Ohms

### The students make this circuit using the same thermistor. Which row of the table shows the conditions for the highest current in the ammeter? • The light shining on the LDR is bright. The temperature across the thermistor is low.
• The light shining on the LDR is bright. The temperature across the thermistor is high.
• The light shining on the LDR is dim. The temperature across the thermistor is low.
• The light shining on the LDR is dim. The temperature across the thermistor is high.

• A. 0.45 W
• B. 0.50 W
• C. 4.5 W
• D. 5.0 W

• A. 0.03 A
• B. 30 A
• C. 33 A
• D. 1600 A

### Some students investigate how the current in a resistor varies with voltage. Which answer is correct for their investigation?

• A. Ammeter in series with the resistor. Voltmeter in series with the resistor.
• B. Ammeter in series with the resistor. Voltmeter in parallel with the resistor.
• C. Ammeter in parallel with the resistor. Voltmeter in series with the resistor.
• D. Ammeter in parallel with the resistor. Voltmeter in parallel with the resistor.

### The students plot a graph of their results. The value of the resistor used is; (V = I x R) • A. 0.05 Ohms
• B. 1.8 Ohms
• C. 2.0 Ohms
• D. 20 Ohms

### The students investigate how the resistance of a thermistor varies with temperature. They produce this graph. When the students warm the thermistor from 0 ºC to 23 ºC, its resistance • A. Increases by about 10 kOhms
• B. Decreases by about 10kOhms
• C. Decreases by about 26 kOhms
• D. Decreases by about 36 kOhms

• A. 9 deg. C
• B. 54 deg. C
• C. 60 deg. C
• D. 70 deg. C