General definitions paper 1

Question 1

Electron volt

Answer 1

work done to accelerate electron through a pd of 1V

Question 2

Ground state

Answer 2

Most stable energy level an electron can exist in

Question 3

Stopping potential

Answer 3

minimum pd needed to stop the highest Ek electrons from leaving the plate in photoelectric effect

Question 4

Material dispersion

Answer 4

waves of diff wavelengths travel at different speeds, causing pulse broadening
Use monochromatic light to fix

Question 5

Modal dispersion

Answer 5

Waves take diff paths through fibre, causing pulse broadening
Use a narrower core to fix

Question 6

EMF

Answer 6

The amount of energy transferred by a source to each unit of charge that passes through it

Question 7

Superconductor

Answer 7

material that has 0 resistivity when temp is below critical temp
used to produce strong mag fields

Question 8

Forced vibrations

Answer 8

repeated up and down oscillations at the frequency of a driver

Question 9

Damping

Answer 9

Dissipation of energy from an oscillating system leading to amplitude of oscillations decreasing

Question 10

Resistivity

Answer 10

Extent to which a material opposes the flow of current through it

Question 11

Frequency

Answer 11

Number of waves that pass a point in a unit time period

Question 12

Breaking stress

Answer 12

Max stress an object can withstand before failing

Question 13

Brittle

Answer 13

Shows very little strain before reaching its breaking stress

Question 14

Elastic limit

Answer 14

Force beyond which an object will no longer deform elastically. When deforming forces are removed, it will not return to its original shape

Question 15

Current

Answer 15

Rate of flow of charge