Electricity Review

• Current

• Diameter

• Length

• Potential difference

A voltmeter is used to measure potential difference for a component X.

Which answer gives the position and ideal resistance for the voltmeter?

• In series with X, with infinite resistance

• In series with X, with zero resistance

• In parallel with X, with infinite resistance

• In parallel with X, with zero resistance

• 0.35 A

• 2.86 A

• 3.50 A

• 7.14 A

A wire has a resistance R.

What is the resistance when both the length and radius of the wire are doubled?

• $\frac{R}{4}$

• $\frac{\text{R}}{2}$

• $2R$

• $4R$

• 500 ohms

• 1700 ohms

• 2000 ohms

• 6000 ohms

A 1.5 m length of wire has a cross-sectional area 5.0 × 10–8 m 2.

When the potential difference across its ends is 0.20 V, it carries a current of 0.40 A. The resistivity of the material from which the wire is made is...

• 6.0 × 10⁷ Ω m

• 1.7 × 10^–8 Ω m

• 1.1 × 10⁶ Ω m

• 9.4 × 10^–7 Ω m

• 0 A

• 0.10 A

• 0.20 A

• 0.40 A

• 111 J

• 390 J

• 6650 J

• 23,400 J

When the light intensity on the LDR increases, what happens on the meter readings?

• The ammeter reading goes up, the voltmeter reading goes up

• The ammeter reading goes down, the voltmeter reading goes down

• The ammeter reading goes down, the voltmeter reading goes up

• The ammeter reading goes up, the voltmeter reading goes down

When the temperature of a copper wire increases, its ability to conduct electricity

• remains the same

• decreases

• increases

• remains the same at first then increases