Magnetism and machines

Question 1 of 10

Fleming's right-hand rule is used to find the direction of

Question 2 of 10

Hysteresis loss in a transformer core is reduced by using

Question 3 of 10

Carbon brushes in a DC motor

Question 4 of 10

An induction motor is widely used because it is

Question 5 of 10

The back e.m.f. of a DC motor with supply 240 V, armature resistance 0.5 Ω and current 20 A is

Question 6 of 10

A transformer has a primary voltage of 240 V and a secondary voltage of 12 V. If the primary has 2,000 turns, find the secondary turns.

Question 7 of 10

The commutator in a d.c. motor

Question 8 of 10

The part of a DC machine that carries the armature winding and rotates is the

Question 9 of 10

A transformer with more secondary turns than primary turns is a

Question 10 of 10

The part of a d.c. motor that reverses the current in the coil every half turn is the