# Current and Charge Flashcards Preview

## Physics, A Level Ocr Spec a > Current and Charge > Flashcards

Flashcards in Current and Charge Deck (13)
1
Q

Kirtchoffs first law

A

Sum of current into a junction is equal to current out

2
Q

The number density of a material

A

Is the number of free electrons per cubic metric (how good a conductor is it)

3
Q

If a wire is made thicker how will this effect the mean sift velocity

A

It slows the mean diff velocity as the particles aren’t tunnelled :directed as much

4
Q

Define one volt

A

V= W/Q

The of pd across a component when 1 house is transferred per coulomb

5
Q

Define one ohm

A

The resistance of a component when one volt is needed to move one amp of current through it

6
Q

Ohms law

A

Voltage and current are directly proportional for a metallic conductor at constant temp

7
Q

Which of these are ohmic?
Resistor
Filament
Diodes (LED)

A

Resistor

8
Q

What Negative temperature coefficient?

A

Thermistor as it acts weird and resistance decreases with heat

9
Q

Define resistivity

A

The product of the resistance and the cross sectional area or a component made of the given material dived by its length

10
Q

Kirtchoffs evening law

A

In a closed loop the sum of the emf equals the sum of the pd

11
Q

Define a progressive wave

A

An oscillation that travels transferring energy

12
Q

Define a longitudinal wave

A

A wave that the transfer of energy is parallel to direction of motion

13
Q

Transverse wave

A

The oscillations are perpendicular to the direction of energy transfer