Paper 1 Current Electricity Fundamentals Drills

Q1

Electric current is

A. charge per unit potential difference.
B. rate of flow of charge.
C. energy per unit charge.
D. resistance per unit length.

Q2

A current of $0.40\mathrm{A}$ flows for $25\mathrm{s}$. Charge transferred is

A. $0.016\mathrm{C}$
B. $10\mathrm{C}$
C. $25.4\mathrm{C}$
D. $62.5\mathrm{C}$

Q3

Potential difference is

A. work done per unit charge.
B. charge per unit time.
C. resistance per unit current.
D. power per unit time.

Q4

Resistance is defined by

A. $R=I/V$.
B. $R=V/I$.
C. $R=VI$.
D. $R=Q/t$.

Q5

An ohmic conductor has

A. constant resistance at constant temperature.
B. current independent of p.d.
C. decreasing p.d. as current increases.
D. zero resistance always.

Q6

Conventional current in a metal is opposite to

A. proton drift.
B. electron drift.
C. electric field direction.
D. energy transfer direction always.

Q7

Resistivity relation is

A. $R=\rho L/A$.
B. $R=\rho A/L$.
C. $R=LA/\rho$.
D. $R=I/V$.

Q8

Increasing wire length with same material and area makes resistance

A. increase.
B. decrease.
C. zero.
D. unchanged.

Q9

Increasing cross-sectional area with same material and length makes resistance

A. increase.
B. decrease.
C. infinite.
D. unchanged.

Q10

Emf of a source is energy transferred

A. from electrical to non-electrical forms per unit charge inside the source.
B. from non-electrical to electrical forms per unit charge by the source.
C. per unit time only.
D. only in a resistor.

Q11

For a real source with emf $\mathcal{E}$ and internal resistance $r$, terminal p.d. when supplying current is

A. $V=\mathcal{E}+Ir$.
B. $V=\mathcal{E}-Ir$.
C. $V=Ir-\mathcal{E}$.
D. $V=I/r$.

Q12

Lost volts refer to p.d. across

A. the external resistor only.
B. the internal resistance.
C. the voltmeter.
D. an open switch.

Q13

Electrical power in a component is

A. $P=VI$.
B. $P=V/I$.
C. $P=I/V$.
D. $P=Q/V$.

Q14

A $6.0\Omega$ resistor has current $2.0\mathrm{A}$. Power dissipated is

A. $12\mathrm{W}$
B. $24\mathrm{W}$
C. $3.0\mathrm{W}$
D. $8.0\mathrm{W}$

Q15

Current density is current per unit

A. length.
B. area.
C. volume.
D. charge.

Q16

The drift-speed relation is

A. $I=nqA{v}_d$.
B. $I=nq{v}_d/A$.
C. $I=A/(nq{v}_d)$.
D. $I=QV$.

Q17

A filament lamp is non-ohmic mainly because its

A. temperature changes, changing resistance.
B. current is always zero.
C. p.d. is not measurable.
D. resistance is independent of temperature.

Q18

The gradient of a $V$ against $I$ graph for an ohmic resistor gives

A. conductance.
B. resistance.
C. charge.
D. power directly.

Q19

The unit of resistivity is

A. $\Omega \mathrm{m}$.
B. $\Omega /\mathrm{m}$.
C. $\mathrm{A}{\mathrm{m}}^{-2}$.
D. $\mathrm{C}{\mathrm{s}}^{-1}$.

Q20

If terminal p.d. decreases linearly with current, the magnitude of the gradient of $V$ against $I$ is

A. emf.
B. internal resistance.
C. external resistance only.
D. charge.