1 markThe graph shows how a potential difference (p.d.) varies with time.
Which of the following is correct?
The frequency is 4.5 Hz.
The peak value is 4.0 V.
The period is 0.20 s.
The root mean square value of p.d. is 1.0 V.
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1 markA wire carries an alternating current of peak value 3 A.
Which of the following is the root-mean-square value of this current?
1.5 A
2.1 A
4.2 A
9.0 A
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1 markA rectangular sheet of aluminium is attached to an air-track glider as shown.
The glider moves towards a region of uniform magnetic field at a constant velocity.
When the glider enters the magnetic field, the magnetic flux is perpendicular to the aluminium sheet.
Which row of the table describes the velocity of the glider as it enters the magnetic field,
when it is completely within the magnetic field and as it leaves the magnetic field?
| Enters the magnetic field | Within the magnetic field | Leaves the magnetic field | |
| A | constant | decreasing | constant |
| B | decreasing | constant | increasing |
| C | decreasing | constant | decreasing |
| D | decreasing | decreasing | decreasing |
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