Circuit Level Processing

The p.d. across a resistor is 12 V. The power dissipated is 6.0 W.

Which statement is correct?

• The charge passing through the resistor in one second is 2.0 coulomb.

• The resistor transfers 6.0 joule for each coulomb passing through the resistor.

• The resistor transfers 12 joule in 2.0 second.

• The resistor dissipates 6.0 joule when the current is 2.0 ampere.

Tags

NGSS.HS-PS3-5

A resistor is connected across a power supply.

Which statement is correct about the conduction electrons in this resistor?

• They travel at the speed of light between collisions with ions.

• They make random collisions with vibrating electrons.

• They travel at their mean drift velocity between collisions.

• They drift towards the positive end of the power supply.

Tags

NGSS.HS-PS3-5

A copper rod of cross-sectional area 3.0 × 10⁻⁴ m² is used to transmit large currents.

A charge of 650 C passes along the rod every 5.0 s. Calculate the current I in the rod.

A copper rod of cross-sectional area 3.0 × 10⁻⁴ m² is used to transmit large currents.

A charge of 650 C passes along the rod every 5.0 s. Calculate the total number of electrons passing any point in the rod per second.

(answer to 3 d.p and standard form in the following formats accepted: 1.23 x 10¹² or 1.23 x 10^12, no units)

A copper rod of cross-sectional area 3.0 × 10⁻⁴ m² is used to transmit large currents.

A charge of 650 C passes along the rod every 5.0 s. Calculate the mean drift velocity of the electrons in the rod given that the number density of free electrons is 1.0 × 10²⁹ m⁻³.

(answer to 2 d.p and standard form in the following formats accepted: 1.2 x 10^-2 or 1.2 x 10^-2, no units)

• 2.7 x 10-5

• 2.7 x 10-4

• 2.7x10-3

• 2.7x10 +5

A battery charger contains a microprocessor circuit so that it can charge an AA rechargeable cell at a constant current of 450 mA. It takes 4 hours 40 minutes to charge a 1.5 V cell from a fully discharged state.

Calculate the charge Q passing through the cell during the charging process. (2 sig fig with units)

A battery of negligible internal resistance is connected across two resistors of resistance values R and 2R as shown in Fig. 24.1.

The same battery is now connected to the same resistors as shown in Fig. 24.2.

Calculate the ratio between the currents of the 2 circuits: = current from battery in circuit 24.1 / current from battery in circuit 24.2

(answer to 2 sig fig, no unit)

Two batteries, each of e.m.f 6.0 V and negligible internal resistance, are joined in parallel. The cells are connected to two identical resistors, joined in parallel.

What is the voltage across each resistor?

• 1.5 V

• 3.0 V

• 6.0 V

• 12.0 V

Tags

NGSS.HS-PS3-5

The circuit in Fig. 2.1 consists of a cell and five resistors.

Calculate the p.d. across the 6.0 Ω resistor. The current at point X is 0.16 A.

(2 sig fig + unit symbol)

The circuit in Fig. 2.1 consists of a cell and five resistors.

Calculate the value of the internal resistance r. The current at point X is 0.16 A.

(2 sig fig, no unit needed)