Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
8 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Define the volt and give a formula |
Energy per unit charge (1V = 1J/C). V=E/Q |
|
|
|
Define current and give a formula. |
The rate of flow of charge. I=Q/t |
|
|
|
Increasing the e.m.f of a circuit will increase.... |
The current |
|
|
|
Why should a voltmeter always be connected in parallel. |
To make the resistance as small as possible. |
|
|
|
Why should an ammeter always be connected in series? |
To make the resistance as small as possible. |
|
|
|
Why is energy lost in a resistor. |
1) Electrons collide more with vibrating metal ions in the resistor. 2) Internal energy is transferred from the electrons to the metal ions 3) This causes some electrical energy to be lost as heat. |
3 steps. |
|
|
Derive formula P = I²R |
Energy lost in a resistor per second = power = IV. V = IR (Substitute into IV) P = I²R |
|
|
|
Draw V/I graphs for: An ohmic resistor, a filament lamp, an LDR, and a diode, and explain why they are the shape that they are. |
OHMIC RESISTOR: Voltage/Current is constant, so gradient is a straight line through the origin. LAMP: Gradient increases as current causes filament to heat up, increasing the resistance as more electrons collide with vibrating metal ions, transferring internal energy. LDR: straight through origin, Higher current = low resistance DIODE: No current flow in one direction. |
|
