A current carrying wire establishes a magnetic field around the wire. How can the magnetic field be increased?
increase the current through the wire, increase the number of loop in the coil, use stronger magnet
Please state the best description how a loudspaker is construced !
an electromagnet, a permanent magnet and a vibrating paper cone
What is the role of the split-ring commutator in an electric motor?
Reverse the direction of current for every half turn.
How can the speed of an electric motor be increased?
Increase the current, increase the number of turn in coil, increase the strength of magnetic field.
A transformer has a soft iron core. Describes why the core must be magnetically soft?
Magnetically soft iron means it can become demagnetised as the current switches direction and then re-magnetised with the field in the opposite direction.
The primary coil on a step-up transformer has 500 coils and is connected to a 12 V supply. What is the output voltage if the secondary coil has 2000 turns?
48 Volt
The secondary coil of a step-down transformer has 100 turns and produces 2 V. What is the number of turns required for a transformer connected to a 10 V supply?
500
A transformer is connected to a 230 V mains supply, 0.25 A. The voltage output on the secondary coil is 12 V. What is the current through the secondary coil?
4.8 Ampere
A transformer is connected to a 12 V supply. The voltage output on the secondary coil is 2 V, with a current of 2.0 A. What is the current through the primary coil?
0.33 Ampere
How is a uniform magnetic field represented?
with equally spaced straight lines between opposite poles.
Add labels to the empty boxes and identify the parts indicated !
Upper box : Split ring commutator, Lower box : Brushes
The coil rotates in a clockwise direction when viewed from point P. State which of the magnetic poles, X or Y, is the N-pole
X is the north pole
