Current-voltage characteristics Quiz
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5 questions, one answer each
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1. Which condition must be met for a metal wire to obey Ohm's law?
- A. Its length must be small
- B. The pd must be less than 1 V
- C. The current must be in the reverse direction
- D. Its temperature must be constant
2. What does the I–V characteristic of a filament lamp look like?
- A. A straight line through the origin
- B. A curve, symmetrical about the origin, whose gradient decreases as the pd increases
- C. A horizontal line
- D. A curve that is zero for negative pd
3. A diode has a pd of 5.0 V in the reverse direction. What is the current?
- A. Large, about 1 A
- B. Equal to the forward current
- C. Almost zero
- D. 5.0 A
4. A graph of pd (vertical axis) against current (horizontal axis) for a resistor is a straight line through the origin with gradient 25 Ω. What is the current when the pd is 10 V?
- A. 2.5 A
- B. 0.40 A
- C. 250 A
- D. 35 A
5. A lamp passes 1.5 A when the pd is 6.0 V, and 2.0 A when the pd is 12 V. What does this show?
- A. The lamp obeys Ohm's law
- B. The resistance decreases as the pd rises
- C. The resistance increases as the pd rises
- D. The resistance is 4.0 Ω at both pds