Chapter 4 Elec, Waves, Quantum Flashcards

1
Q

Equation linking current charge and time?

A

I=delta Q/ delta t

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2
Q

Electric charge is measured in

A

coulombs (C)

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3
Q

Elementary charge is

A

1.6 x 10^-19

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4
Q

Charges of electrons, protons and neutrons

A

Electron - -e
Proton - +e
Neutron - 0

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5
Q

Equation linking total charge number of electrons and elementary charge

A

Q=ne

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6
Q

Define electric current

A

Rate of flow of charge

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7
Q

What are the charge carriers in solutions?

A

Ions

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8
Q

Conventional current flows from

A

The positive terminal towards the negative terminal

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9
Q

Electrons travel from

A

The negative terminal towards the positive terminal

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10
Q

Ammeters are placed in

A

Series

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11
Q

The conservation of charge states

A

Electrical charge can neither be created or destroyed

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12
Q

What is Kirchoff’s first law?

A

The sum of the currents entering any point in a circuit is equal to the sum of the currents leaving that same point

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13
Q

Number density is

A

The number of free electrons per cubic metre of material

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14
Q

Equation linking current, cross sectional area, number density, elementary charge and mean drift velocity

A

I=nAve

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15
Q

What effect does a greater cross sectional area have on drift velocity?

A

Decreases (if constant current)

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16
Q

Three equations for calculating power

A

P=w/t
P=IV
P=I^2R
P=v^2/R

17
Q

How many joules are in a kWh?

A

3.6 x 10^6

18
Q

Define the volt?

A

The pd when 1 joule of energy is transferred per coulomb

19
Q

Voltmeters are connected in

20
Q

What is thermionic emission?

A

The emission of electrons through the action of heat

21
Q

In an electron gun the greater the accelerating pd

A

the energy is transferred to the electrons so the faster they move

22
Q

Define resistance

A

The ratio of pd to current across the component

23
Q

Define the Ohm

A

Resistance when apd of 1v is produce by an ampere of current

24
Q

What is Ohm’s law?

A

For a metallic conductor kept at constant temperature, the pd across the component is directly proportional to the current

25
A photon is
a quantum of electromagnetic energy
26
What are the two equations for the energy of a photon?
E=hf | E=hc/lambda
27
Define the electron volt
the energy transferred to or from an electron when it passes though a pd of one volt
28
Evidence for the wave nature of light includes:
interference and diffraction
29
Evidence for the particulate nature of light includes
the photoelectric effect
30
Work function is defined as
the minimum energy needed to remove a single electron from the surface of a particular metal
31
Threshold frequency is defined as
the minimum frequency of the EM radiation that will cause the emission of an electron from the surface of a particular metal
32
Which quantity is conserved when a photon interacts with an electron is
energy
33
The number of electrons emitted from a metal surface is proportional to
intensity (provided the frequency is above the threshold frequency)
34
Evidence for the wave nature of electrons includes
electron diffraction