3/. If three lamps were connected in series and each had the same resistance, what would be the voltage dropped across each one if the supply voltage was 230 V?
5/. Three resisters of 4 Ω, 16 Ω and 24 Ω are connected in parallel. If the supply voltage is 110 V, what will be the:
i/. total resistance:
ii/. current in each leg of the circuit:
iii/. total current:
6/. Four resisters are connected in a series/parallel circuit. The 6 Ω and 12 Ω resistors are connected in parallel with each other and are then connected in series with the 17 Ω and 27 Ω resistors that are also connected in parallel with each other. If the supply voltage is 230 V, calculate:
i/. Total resistance:
ii/. Total current:
iii/. Voltage dropped across each network:
iv/. Current in each leg of the networks:
7/. A cell has a terminal voltage of 1.95 V when supplying a current of 8.2 A. The terminal voltage rises to 2.1 V when the load is switched off. What is the internal resistance of the cell?
8/. Two resistors of 5 Ω and 10 Ω are connected in parallel across a battery. The e.m.f of the battery is 24V and the internal resistance is 1.2 Ω. Determine the total current in the circuit and terminal voltage of the battery. What will be the voltage dropped across the two parallel resistors?
1/. Name three factors that affect the size of the induced emf?
2/. If the induced e.m.f in a coil is 220 V, it's length per turn is 75 mm and it has 700 turns, what will be its velocity within the magnetic field if its magnetic flux density is 0.35 T?
3/. What two rules can be used to determine the direction of the induced e.m.f?
4/. A conductor is moved through through a magnetic field of strength 380 mT. If there are 850 turns and the diameter of the former that the coil is wound is150 mm. What will be the force applied to the conductor when it has a current of 0.25 A flowing in it?
5/. What is the difference between self and mutual induction, and give an example of each?
6/. An electromagnet has an inductance of 14 H. If the current in the coil falls from 2.5 A to 1.1 A in 10 ms, what will be the average induced emf?
7/. The current in an air-cored coil increases from 0.5 A to 25 A in 0.25 s. If the inductance is 1.5 H, what will be the induced emf?
8/. The coil of an electric bell has an inductance of 2.1 H. Calculate the e.m.f induced in the coil when a current of 0.15 A is reduced to zero in 15 ms.