µ IB | Electric Fields

10 quick questions

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

 

 

 1. A current of 2 amps flows along a conductor. Which of these statements correctly describes this current?

  • A. 2 coulombs of charge flows past one point.
  • B. 2 coulombs of charge flows past one point per second.
  • C. 2 joules of energy is transferred.
  • D. 2 joules of energy is transferred per second.

 

2. Which of these answers best describes the name and polarity of the charge carrier in a metal conductor?

Name of charge carrier polarity of charge carrier
A
electron negative
B
proton negative
C
electron positive
D
proton positive

 

3&4. A cell is connected to a motor.

A charge of 12 coulombs flows through the motor in 3 seconds. The voltage of the cell is 6 V, and it has a negligible internal resistance.

 

3. What is the current flowing in the circuit?

  • A. 0.25 A
  • B. 2 A
  • C. 4 A
  • D. 36 A

4. What work has been done by the cell in this time?

  • A. 6 J
  • B. 36 J
  • C. 48 J
  • D. 72 J

 

5. An electronvolt is a unit of...

  • A. energy
  • B. potential difference
  • C. power
  • D. electric field strength

Two charges +Q are seperated by a distance r. There is a repulsion force F acting between the 2 charges as shown:

 

6. What would happen to the size of the force if the charges are moved to a distance of ½ r?

  • A. ¼ F
  • B. ½ F
  • C. 2 F
  • D. 4 F

7. Which of these changes would increase the force to 6F?

  • A. Increase the original distance to 3r.
  • B. Decrease the original distance by a factor of 3.
  • C. Keep the original distance, but increase both charges to + 3 Q.
  • D. Keep the original distance, but increase both charges to + √6 Q.

 

8. Two copper rods, P and Q, have identical currents flowing through them. P has a smaller diameter than Q.

Which of these answers best describes the differences between values of 'n' and 'v' in both rods, using the formula I = nAvq?

Value of n Value of v
A
Identical in both rods Greater in rod P
B
Greater in rod P Greater in rod P
C
Greater in rod P Greater in rod Q
D
Greater in rod Q Identical in both rods

 

9. At which point in this diagram is the electric field due to the 2 charges equal to zero?

 

10. The sign of the right hand charge has now been reversed. At which point in this diagram is the electric field zero?