Applied Electricity SAQ

Play an AI-generated podcast conversation about this lesson

What is the primary function of an electromagnetic relay?

To switch on and off a current in a second circuit based on the current flowing through the primary circuit

What component of the electromagnetic relay is responsible for attracting the armature and forcing the contacts together in the secondary circuit?

The electromagnet

What is an example of a use of an electromagnetic relay in a vehicle?

To control the starter motor

How can electromagnetic relays be used in audio amplifiers?

To control a high-voltage circuit with a low-voltage signal Signup and view all the answers

What is another function of electromagnetic relays besides controlling circuits?

As protection relays by opening and closing circuit breakers Signup and view all the answers

What is the principle behind the operation of a simple d.c. motor?

A current-carrying conductor in a magnetic field experiences a force. Signup and view all the answers

What is the direction of the force experienced by a current-carrying conductor in a magnetic field?

Perpendicular to both the direction of the current and the magnetic field. Signup and view all the answers

What is the energy conversion that takes place in an electric motor?

Electrical energy to kinetic energy. Signup and view all the answers

What is the formula for the force experienced by a current-carrying conductor in a magnetic field?

F = IlB sin⁡θ Signup and view all the answers

What is the role of the magnet in a simple d.c. motor?

It creates torque on the coil by interacting with the magnetic field around it. Signup and view all the answers

What is the principle behind the movement of a coil in a moving-coil loudspeaker?

The principle that a current-carrying conductor in a magnetic field experiences a force. Signup and view all the answers

How is a moving-coil galvanometer converted to an ohmmeter?

By connecting a variable resistance and a battery in series with it. Signup and view all the answers

What is the purpose of the cardboard tube in a moving-coil loudspeaker?

To support the coil of wire. Signup and view all the answers

What is the result of passing an alternating current through the coil of a moving-coil loudspeaker?

The paper cone moves back and forth, creating sound waves. Signup and view all the answers

What is the common principle behind the operation of a moving-coil loudspeaker and a moving-coil galvanometer?

The principle that a current-carrying conductor in a magnetic field experiences a force. Signup and view all the answers

What is the significance of the negative sign in the equation E = -N dΦ/dt?

The negative sign indicates that the induced emf opposes the change causing it. Signup and view all the answers

What is the purpose of the soft iron core in an induction coil?

To increase the magnetic flux and hence induced emf. Signup and view all the answers

What is the principle behind the operation of an induction coil?

Electromagnetic induction, where a change in magnetic flux induces an emf. Signup and view all the answers

What is the significance of the adjustable spark gap in an induction coil?

It allows the output voltage to be adjusted. Signup and view all the answers

What is an example of a practical application of an induction coil?

Car spark plugs and electric fences. Signup and view all the answers

What is the main characteristic of an alternating current?

The direction reverses periodically Signup and view all the answers

How does the rotation of the coil in an a.c. generator affect the magnetic field?

It causes the area cutting the magnetic field to vary, inducing an alternating emf in the coil Signup and view all the answers

What is the role of the stationary magnets in an induction motor?

They produce a varying magnetic field Signup and view all the answers

Who is credited with the invention of the induction motor?

Nikola Tesla Signup and view all the answers

What is the common application of induction motors in household appliances?

They are used in fans, fridges, vacuum cleaners, washing machines, etc. Signup and view all the answers

What is the purpose of a transformer in electrical power systems?

to change the voltage of a.c. power supplies Signup and view all the answers

What is a characteristic of a diode?

allows current to flow in one direction only Signup and view all the answers

What is the function of an LED?

emits light when current flows through it Signup and view all the answers

What is a photodiode used for?

to detect the presence of light or to measure its intensity Signup and view all the answers

What type of material is used to make diodes, LEDs, and photodiodes?

semiconductor material Signup and view all the answers