Electircity And Power Eout Flashcards
(28 cards)
What is the purpose of insulation in domestic appliances?
Protects the device or user
What is double insulation?
A safety feature that provides extra protection against electric shock
What is earthing?
A method of protecting users by connecting the electrical circuit to the ground
What is the role of fuses in an electrical circuit?
To protect devices by breaking the circuit in case of excessive current
What happens to electrical energy in a resistor?
Results in the electrical transfer of energy and an increase in temperature
What is the relationship between power, current, and voltage?
Power = current × voltage (P = I x V)
How is energy transferred in an electrical circuit?
Energy transferred = current × voltage × time (E = I x V x t)
What is the difference between alternating current (a.c.) and direct current (d.c.)?
a.c. changes direction periodically; d.c. flows in one direction
When is a series circuit more appropriate?
In applications where the same current must pass through all components
How does the current in a series circuit depend on voltage?
It depends on the applied voltage and the number and nature of other components
How does current vary with voltage in wires?
It can be described experimentally through Ohm’s law
What is the qualitative effect of changing resistance on current?
Increasing resistance decreases current
What are light-dependent resistors (LDRs)?
Resistors whose resistance varies with illumination
What is a thermistor?
A resistor whose resistance varies with temperature
How can lamps and LEDs be used in circuits?
To indicate the presence of a current
What is the relationship between voltage, current, and resistance?
Voltage = current × resistance (V = I x R)
Define current in terms of charge.
Current is the rate of flow of charge
What is the relationship between charge, current, and time?
Charge = current × time (Q = I x t)
What type of charge flows in solid metallic conductors?
Negatively charged electrons
What does it mean that current is conserved at a junction?
The total current entering a junction equals the total current leaving
What is the voltage across two components connected in parallel?
The same across both components
How do you calculate currents in a series circuit?
By applying Ohm’s law to the resistive components
What is voltage in terms of energy?
Voltage is the energy transferred per unit charge passed
What is the formula for gravitational potential energy?
Gravitational potential energy = mass × gravitational field strength × height (GPE = m x g x h)
