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1. A cell of emf 6.0 V and negligible internal resistance is connected to three resistors as shown.
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The resistors have resistance of 3.0 Ω and 6.0 Ω as shown.
What is the current in resistor X?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
 | | 0.40 A | |
| | 0.50 A | |
|  | 1.0 A | |
| | 2.0 A |
2. A filament lamp and a semiconducting diode have the voltage–current
Wrong
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(V–I) characteristics shown and are connected in parallel.
What is the resistance of the lamp and the resistance of the diode when the current in each device is 2.0 A?
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3. Four point charges of magnitudes +q, +q, −q, and −q are held in place at the corners of a square of side r.
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The Coulomb constant is k. Which of the following is the electrical potential at the centre of the square O?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | 0 | |
| | `(4kq)/r` | |
| | `(4kqsqrt2)/r` | |
| | `(-4kqsqrt2)/r^2` |
4. When an electric cell of negligible internal resistance is connected to a resistor of resistance 4R, the power dissipated in the resistor is P. What is the power dissipated in a resistor of resistance value R when it is connected to the same cell?
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| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | `p/4` | |
| | P | |
| | 4P | |
| | 16P |
5. A circuit is formed by connecting a resistor between the terminals of a battery of electromotive force (emf) 6 V. The battery has internal resistance. Which statement is correct when 1 C of charge flows around the complete circuit?
Wrong
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| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | 6 V is the potential difference across the resistor. | |
| | 6 J of thermal energy is dissipated in the battery. | |
| | 6 J of chemical energy is transformed in the battery. | |
| | 6 J of thermal energy is dissipated in the resistor. |
6. An ion of charge +Q moves vertically upwards through a small distance s in a uniform vertical electric field. The electric field has a strength E and its direction is shown in the diagram.
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What is the electric potential difference between the initial and final position of the ion?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | `(EQ)/s` | |
| | EQs | |
| | Es | |
| | `E/s` |
7. A 12V battery has an internal resistance of 2.0Ω. A load of variable resistance is connected across the battery and adjusted to have resistance equal to that of the internal resistance of the battery. Which statement is correct for this circuit?
Wrong
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| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | The current in the battery is 6A. | |
| | The potential difference across the load is 12V. | |
| | The power dissipated in the battery is 18W. | |
| | The resistance in the circuit is 1.0Ω. |
8. A proton p is at rest between the poles of two horizontal magnets as shown below.
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The magnetic force on the proton is
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | from left to right. | |
| | from top to bottom. | |
| | into the plane of the paper. | |
| | zero |
9. The diagram shows the path of a particle in a region of uniform magnetic field. The field is directed into the plane of the page.
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This particle could be
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | an alpha particle. | |
| | a beta particle. | |
| | a photon. | |
| | a neutron. |
10. A current carrying wire is in the same plane as a uniform magnetic field. The angle between the wire and the magnetic field is θ.
Wrong
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The magnetic force on the current carrying wire is
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | zero. | |
| | into the plane of the paper. | |
| | out of the plane of the paper. | |
| | at an angle θ to the direction of the magnetic field. |
11. Electrons, each with a charge e, move with speed v along a metal wire. The electric current in the wire is I.
Wrong
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Plane P is perpendicular to the wire. How many electrons pass through plane P in each second?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | `e/I` | |
| | `(ve)/I` | |
| | `I/(ve)` | |
| | `I/(e)` |
12. An ion follows a circular path in a uniform magnetic field. Which single change decreases the radius of the path?
Wrong
Score: 0 / 1
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | Increasing the mass of the ion | |
| | Increasing the charge of the ion | |
| | Increasing the speed of the ion | |
| | Decreasing the magnetic flux density of the field |
13. A resistor has a resistance R. The potential difference across the resistor is V. Which of the following gives the energy dissipated in the resistor in time t?
Wrong
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| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | `(Vt)/R` | |
| | `(Rt)/V^2` | |
| | RV2t | |
| | `(V^2t)/R` |
14. The electric potential is
Wrong
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VR at a point R in an electric field and at another point S the electric potential is VS. Which of the following is the work done by the electric field on a point charge +q as it moves from R to S?
| Your choice | Expected choice | Answer | Comment |
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| | VR-VS
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| | q(VR-VS)
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| | VS-VR
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| | q(VS-VR) |
15. Two wires, X and Y, are made from the same metal. The wires are connected in series. The radius of X is twice that of Y. The carrier drift speed in X is
Wrong
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vX and in Y it is vY.
What is the value of the ratio `(vX)/(vY)?`
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | 0.25 | |
| | 0.50 | |
| | 2.00 | |
| | 4.00 |
16. A copper wire with length L and radius r has a resistance R.
Wrong
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What is the radius of a copper wire with length `L/2` and resistance R?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | 2r | |
| | `sqrt2r` | |
| | `r/sqrt2` | |
| | `r/2` |
17. Positive charge is uniformly distributed on a semi-circular plastic rod. What is the direction of the electric field strength at point S?
Wrong
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| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | A | |
| | B | |
| | C | |
| | D |
18. Two resistors, of resistance
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R1 and R2, are connected in series with a cell of emf ε and negligible internal resistance.
Which expression gives the potential difference across the resistor of resistance R1?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | `(R_1/(R_1+R_2))epsi` | |
| | `((R_1+R_2)/R_1)epsi` | |
| | `(R_2/(R_1+R_2))epsi` | |
| | `((R_1+R_2)/R_2)epsi` |
19. A voltmeter of resistance 50kΩ is used to measure the electric potential difference in a circuit, as shown. The cell has an electromotive force (emf) of 5.0V and negligible internal resistance.
Wrong
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What is the reading on the voltmeter?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | 1.0 V | |
| | 1.7 V | |
| | 4.0 V | |
| | 5.0 V |
20. A positively charged particle follows a circular path as shown below.
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Which of the following electric fields could have caused the charged particle to follow the above path?
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21. A metal rod M is falling vertically within a horizontal magnetic field. The metal rod and magnetic field are directed into the paper. What is the direction of the initial force acting on the metal rod that is predicted by Lenz’s law?
Correct
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| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | A | |
| | B | |
| | C | |
| | D |
22. A circuit consists of a cell of electromotive force (emf) 6.0V and negligible internal resistance connected to two resistors of 4.0Ω.
Wrong
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The ammeter has resistance equal to 1.0Ω and the voltmeter is ideal. What are the readings of the ammeter and the voltmeter?
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23. Two isolated point charges,
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-7μC and +2μC, are at a fixed distance apart. At which point is it possible for the electric field strength to be zero?
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | A | |
| | B | |
| | C | |
| | D |
24. An ideal ammeter is used to measure the current in a resistor. Which of the following gives the resistance of an ideal ammeter and the way it is connected to the resistor?
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25. The diagram below shows a uniform electric field of strength E. The field is in a vacuum.
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An electron enters the field with a velocity v in the direction shown. The electron is moving in the plane of the paper. The path followed by the electron will be
| Your choice | Expected choice | Answer | Comment |
|---|---|---|---|
| | parabolic. | |
| | in the direction of E. | |
| | in the direction of v. | |
| | circular. |
26. A long straight wire carries an electric current perpendicularly out of the paper. Which of the following represents the magnetic field pattern due to the current?
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27. The diagram shows the magnetic field surrounding two current-carrying metal wires P and Q. The wires are parallel to each other and at right angles to the plane of the page.
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What is the direction of the electron flow in P and the direction of the electron flow in Q?
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28. A lamp is connected to an electric cell and it lights at its working voltage. The lamp is then connected to the same cell in a circuit with an ideal ammeter and an ideal voltmeter. Which circuit allows the lamp to light at the original brightness?
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29. The diagram shows an electric circuit containing a potentiometer of maximum resistance R. The potentiometer is connected in series with a resistor also of resistance R. The electromotive force (emf) of the battery is 6 V and its internal resistance is negligible.
Wrong
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The slider on the potentiometer is moved from P1 to P2. Which graph shows the variation of the voltmeter V reading with slider distance d?
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