10 minutes maximum! (can you do it in 5?)

1. Resistance is measured in 'Ω'. This is the symbol for the unit .....
 A. watts.
 B. ohms.
 C. resists.
 D. coulombs.


2. The formula to calculate resistance (often called Ohm's Law) is
 A. resistance = voltage x current^{2} (R=V.I^{2})
 B. resistance = voltage ÷ current (R= V/I)
 C. resistance = current ÷ voltage (R= I/V)
 D. resistance = voltage x current (R=V.I)


3. 0.3 kΩ is the same as
 A. 3Ω
 B. 30Ω
 C. 300Ω
 D. 3000Ω


4. What is the resistance of this resistor? 

 A. 0.2Ω
 B. 2Ω
 C. 5Ω
 D. 80Ω


5. What current flows in this circuit? 

 A. 0.2A
 B. 2A
 C. 5A
 D. 150A



6. What is '2mA' in amps?
 A. 2000A
 B. 200A
 C. 0.02A
 D. 0.002A





7. What is the voltage of this power supply?
 A. 1.5 mV
 B. 6V
 C. 15V
 D. 6000V


8. A steel wire has a resistance. Which of these correctly describes the change to the resistance if the wire is made longer, or thicker? (with a bigger radius).

Longer wire 
Thicker wire 
A 
higher resistance 
lower resistance 
B 
lower resistance 
higher resistance 
C 
lower resistance 
lower resistance 
D 
higher resistance 
higher resistance 


Q9 & 10.
In this circuit, a single resistor R is connected to a cell. The total current is given by the ammeter shown.


9. If I change the circuit and put 2 of these resistors in series, what happens? 

 A. The current increases as the total resistance increases.
 B. The current increases as the total resistance decreases.
 C. The current decreases as the total resistance increases.
 D. The current decreases as the total resistance decreases.


10. How does the total current change , compared to a single resistor, if I put 2 of the resistors in parallel? 

The total current is
. 
