Electricity

A circuit is formed by connecting a resistor between the terminals of a battery of electromotive force (emf) 6 V. The battery has internal resistance. Which statement is correct when 1 C of charge flows around the complete circuit?

• 6 V is the potential difference across the resistor.

• 6 J of thermal energy is dissipated in the battery

• 6 J of chemical energy is transformed in the battery.

• 6 J of thermal energy is dissipated in the resistor.

Four resistors are connected as shown.

What is the total resistance between X and Y?

• 3 Ω

• 4 Ω

• 6 Ω

• 24 Ω

An electric dipole consists of a positive and a negative charge separated by a fixed distance. The electric field due to the dipole is shown in the diagram below.

An electric force acts on an electron at point P.

In which direction does this force act?

• direction A

• direction B

• direction C

• direction D

What is the definition of electric current?

• The ratio of potential difference across a component to the resistance of the component

• The power delivered by a battery per unit potential difference

• The rate of flow of electric charge

• The energy per unit charge dissipated in a power supply

• 1

• 2

• 4

• 8

A cylindrical resistor of volume V and length l has resistance R. The resistor has a uniform circular cross-section. What is the resistivity of the material from which the resistor is made?

The graph shows the variation of current I with the potential difference V in a device.

What is the resistance of the device at point P?

• Gradient of the graph at P

A lamp is connected to an electric cell and it lights at its working voltage. The lamp is then connected to the same cell in a circuit with an ideal ammeter and an ideal voltmeter. Which circuit allows the lamp to light at the original brightness?

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A positive point charge P and a negative point charge Q of equal magnitude are held at fixed positions. Y is midway between P and Q.

Which of the following gives the direction of the electric field due to the charges at X, Y and Z?

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