B.5.1 Energy Sources and Circuit Representation

What does emf stand for?

Electromotive force.

What is the role of solar cells in generating emf?

Solar cells convert light energy into electrical energy by exciting electrons when sunlight strikes their surface.

Is emf a force?

No, emf is the energy provided per unit charge, measured in volts (V).

List one advantage and one disadvantage of chemical cells.

Advantage: Portable and compact. Disadvantage: Limited lifespan; requires replacement or recharging.

How do chemical cells generate emf?

Chemical cells create a potential difference between the positive and negative terminals through chemical reactions, driving the movement of electrons.

What is the difference between emf and potential difference?

Emf is the work done per unit charge to move a charge around a circuit, while potential difference is the work done per unit charge between two points in a circuit.

What is a common mistake to avoid when reading circuit diagrams?

Confusing the direction of electron flow with conventional current.

What is the purpose of a circuit diagram?

Circuit diagrams are simplified visual representations that use standardized symbols to communicate the arrangement of electrical components.

List one advantage and one disadvantage of solar cells.

Advantage: Renewable and environmentally friendly. Disadvantage: Dependent on sunlight, making them ineffective at night or in low-light conditions.

What is the direction of conventional current flow?

Conventional current flows from the positive terminal to the negative terminal of the power source.

What is the symbol for a resistor in a circuit diagram?

A resistor is represented by a rectangle.

What is the formula for calculating emf?

emf =W/q Where W is work done in joules and q is charge in coulombs.

What does a battery represent in a circuit diagram?

A battery represents a source of emf.

What are the steps to draw a circuit diagram?

1. Identify all components 2. Use appropriate symbols 3. Connect symbols with straight lines 4. Indicate the direction of conventional current.

What components are in a simple flashlight circuit?

A battery (source of emf), a switch (to control current), and a bulb (to produce light).

What should you do first when analyzing a circuit diagram?

Locate the source of emf and trace the flow of current through the circuit.

What is the symbol for a switch in a circuit diagram?

A switch is represented by a break in the line.