3.5.1.4 Circuits Flashcards
What is power?
Power is defined at the rate of energy transfer or the rate of work done.
What is power measured in?
Power is measured in watts (W). 1 watt is equivalent to 1 joule per second.
What is the equation for power?
Power = Energy Transfer / Time
What is the equation for the power of an electrical component?
Power = Current x Potential Difference
Describe a heating effect of a electric current.
The heating effect of an electric current in any component is due to the resistance of the component.
The charge carriers repeatedly collide with the positive ions of the conducting material.
There is a net transfer of energy from the charge carriers to the positive ions, due to collisions.
After a charge carrier loses Kinetic energy in such a collision, the force due to the p.d. across the material accelerates the charge carrier until it collides with another positive ion.
What is the power of a component with a heating effect?
Power = Current^2 x Resistance. Power = Potential Difference^2 / Resistance.
Give three equations for calculating the energy across an electrical component.
E = IVt
E =( V²/R ) x t
E = I²Rt
Give three equations for calculating the energy across an electrical component.
E = IVt
E =( V²/R ) x t
E = I²Rt
How do you convert between KWh and joules?
1 KWh = 3.6 x10^6 J
How do you convert between KWh and joules?
1 KWh = 3.6 x10^6 J
What does the conservation of charge state?
As charge flows through a circuit, it does not get used up or is not lost. Whatever charge flows into a junction in a circuit, the same amount will flow out of the junction.
What does the conservation of energy state?
Energy is conserved in a closed system.
In a closed loop circuit, the sum of the potential differences must be equal to the emf of the cell.
What does Kirchhoff’s First Law state?
The total current entering a junction is equal to the total current leaving the same junction.
What does Kirchhoff’s Second Law state?
The total electromotive force around a series circuit is equal to the sum of the potential differences across each component.
What is the rule for current in a series circuit?
The current is the same everywhere in a series circuit.
