Electricity and magnetism

28 A 12 V battery is connected to a resistor of resistance 100  . How much charge passes through the resistor in 30 minutes? A 3.6 C B 220 C C 250 C D 15 000 C

28 A student investigates electrostatic charge using a balloon and a cloth. The balloon and cloth are initially uncharged. The student rubs the balloon with the cloth. The balloon gains a negative charge of magnitude Q . The cloth becomes charged and a force acts between the balloon and the cloth. Which row correctly describes the magnitude and sign of the charge on the cloth and the type of force between the balloon and the cloth? magnitude of charge on cloth sign of charge on cloth type of force A equal to Q positive attraction B equal to Q negative repulsion C greater than Q positive repuls

© UCLES 2025 5054/11/M/J/25 29 A circuit consists of a resistor connected between the positive terminal and the negative terminal of a power supply. Which row describes the direction of conventional current and the direction of flow of free electrons in the resistor? direction of conventional current direction of flow of free electrons A from negative to positive from negative to positive B from negative to positive from positive to negative C from positive to negative from negative to positive D from positive to negative from positive to negative 13

© UCLES 2025 5054/11/O/N/25 [Turn over 29 A student connects four circuits using two identical cells, two identical resistors and a motor. In which circuit does the coil of the motor rotate the fastest? M A M B M C M D 14

30 The diagram shows a lightning strike. Charge flows between the cloud and objects on the ground. not to scale cloud lightning ground During the lightning strike, there is a current of 2.8  10 4 A between the cloud and the house for 52 ms. How much charge flows during the lightning strike? A 1500 C B 15 000 C C 24 000 C D 54 000 C

30 The graph shows how the resistance of a thermistor varies with temperature. 160 140 120 100 80 60 40 20 0 0 5 10 15 20 25 30 35 40 45 50 temperature / °C resistance /
The thermistor is at a temperature of 10 °C and is connected in series with a fixed resistor of resistance 20  . What is the combined resistance of both components? A 16  B 20  C 80  D 100 

© UCLES 2025 5054/11/M/J/25 [Turn over 31 Each of the resistors in the circuit shown has a resistance of 6.0  . 6.0
6.0
6.0
What is the total resistance of the circuit? A 2.0  B 4.0  C 9.0  D 18  14