3.3 Collisions of electrons with atoms

1. 3.3 Collisions of electrons with atoms Ionisation - any process of creating ions ( removing an electron from an atom creates a positive ion) * alpha beta gamma radiation creates + ve ions * electrons colliding with atoms of gas in a tube + ve ions

2. 3.3 Collisions of electrons with atoms Ionisation - any process of creating ions ( removing an electron from an atom creates a positive ion) * alpha beta gamma radiation creates + ve ions * electrons colliding with atoms of gas in a tube + ve ions

3. 3.3 Collisions of electrons with atoms Ionisation - any process of creating ions ( removing an electron from an atom creates a positive ion) * alpha beta gamma radiation creates + ve ions * electrons colliding with atoms of gas in a tube + ve ions

4. 3.3 Collisions of electrons with atoms Ionisation - any process of creating ions ( removing an electron from an atom creates a positive ion) * alpha beta gamma radiation creates + ve ions * electrons colliding with atoms of gas in a tube + ve ions

5. 3.3 Collisions of electrons with atoms Ionisation - any process of creating ions ( removing an electron from an atom creates a positive ion) * alpha beta gamma radiation creates + ve ions * electrons colliding with atoms of gas in a tube + ve ions

6. Measuring ionisation energy Electrons are emitted from a hot filament in a tube of gas at low pressure and are attracted to an anode at the other end by a voltage V * Initially the current is small as just a few electrons reach the anode • As the pd is increased the electrons’ speed increases until ionisation • occurs near the anode and the current rises considerably. From; V = W Q W = work done on each electron of charge e by filament = KE of each electron = Ionisation of gas atom = eV

7. Measuring ionisation energy Electrons are emitted from a hot filament in a tube of gas at low pressure and are attracted to an anode at the other end by a voltage V * Initially the current is small as just a few electrons reach the anode • As the pd is increased the electrons’ speed increases until ionisation • occurs near the anode and the current rises considerably. From; V = W Q W = work done on each electron of charge e by filament = KE of each electron = Ionisation of gas atom = eV

8. Measuring ionisation energy Electrons are emitted from a hot filament in a tube of gas at low pressure and are attracted to an anode at the other end by a voltage V * Initially the current is small as just a few electrons reach the anode • As the pd is increased the electrons’ speed increases until ionisation • occurs near the anode and the current rises considerably. From; V = W Q W = work done on each electron of charge e by filament = KE of each electron = Ionisation of gas atom = eV

9. Measuring ionisation energy Electrons are emitted from a hot filament in a tube of gas at low pressure and are attracted to an anode at the other end by a voltage V * Initially the current is small as just a few electrons reach the anode • As the pd is increased the electrons’ speed increases until ionisation • occurs near the anode and the current rises considerably. From; V = W Q W = work done on each electron of charge e by filament = KE of each electron = Ionisation of gas atom = eV

10. Measuring ionisation energy Electrons are emitted from a hot filament in a tube of gas at low pressure and are attracted to an anode at the other end by a voltage V * Initially the current is small as just a few electrons reach the anode • As the pd is increased the electrons’ speed increases until ionisation • occurs near the anode and the current rises considerably. From; V = W Q W = work done on each electron of charge e by filament = KE of each electron = Ionisation of gas atom = eV

11. Measuring ionisation energy Electrons are emitted from a hot filament in a tube of gas at low pressure and are attracted to an anode at the other end by a voltage V * Initially the current is small as just a few electrons reach the anode • As the pd is increased the electrons’ speed increases until ionisation • occurs near the anode and the current rises considerably. From; V = W Q W = work done on each electron of charge e by filament = KE of each electron = Ionisation of gas atom = eV

12. Measuring ionisation energy Electrons are emitted from a hot filament in a tube of gas at low pressure and are attracted to an anode at the other end by a voltage V * Initially the current is small as just a few electrons reach the anode • As the pd is increased the electrons’ speed increases until ionisation • occurs near the anode and the current rises considerably. From; V = W Q W = work done on each electron of charge e by filament = KE of each electron = Ionisation of gas atom = eV

13. The electron volt eV • is a unit of energy equal to the work done when an electron is accelerated • through a pd of 1volt From; V = W Q W = QV but for an electron Q = e = 1.6x 10 -19 C Q1. Calculate the following in Joules: The KE of an electron accelerated through a pd of a. 1 Volt b. 1000 Volt c. 1 MV Q2. State the work done on each electron in eV for the question above. Q3. Calculate the work done (eV) on an ion of charge +2 when accelerated across 100V. Q4 What voltage is required to accelerate an electron of mass 9.1 x10-31 kg to 10% of the speed of light? c = 3 x 10 8 m/s

14. The electron volt eV • is a unit of energy equal to the work done when an electron is accelerated • through a pd of 1volt From; V = W Q W = QV but for an electron Q = e = 1.6x 10 -19 C Q1. Calculate the following in Joules: The KE of an electron accelerated through a pd of a. 1 Volt b. 1000 Volt c. 1 MV Q2. State the work done on each electron in eV for the question above. Q3. Calculate the work done (eV) on an ion of charge +2 when accelerated across 100V. Q4 What voltage is required to accelerate an electron of mass 9.1 x10-31 kg to 10% of the speed of light? c = 3 x 10 8 m/s

15. The electron volt eV • is a unit of energy equal to the work done when an electron is accelerated • through a pd of 1volt From; V = W Q W = QV but for an electron Q = e = 1.6x 10 -19 C Q1. Calculate the following in Joules: The KE of an electron accelerated through a pd of a. 1 Volt b. 1000 Volt c. 1 MV Q2. State the work done on each electron in eV for the question above. Q3. Calculate the work done (eV) on an ion of charge +2 when accelerated across 100V. Q4 What voltage is required to accelerate an electron of mass 9.1 x10-31 kg to 10% of the speed of light? c = 3 x 10 8 m/s

16. The electron volt eV • is a unit of energy equal to the work done when an electron is accelerated • through a pd of 1volt From; V = W Q W = QV but for an electron Q = e = 1.6x 10 -19 C Q1. Calculate the following in Joules: The KE of an electron accelerated through a pd of a. 1 Volt b. 1000 Volt c. 1 MV Q2. State the work done on each electron in eV for the question above. Q3. Calculate the work done (eV) on an ion of charge +2 when accelerated across 100V. Q4 What voltage is required to accelerate an electron of mass 9.1 x10-31 kg to 10% of the speed of light? c = 3 x 10 8 m/s

17. The electron volt eV • is a unit of energy equal to the work done when an electron is accelerated • through a pd of 1volt From; V = W Q W = QV but for an electron Q = e = 1.6x 10 -19 C Q1. Calculate the following in Joules: The KE of an electron accelerated through a pd of a. 1 Volt b. 1000 Volt c. 1 MV Q2. State the work done on each electron in eV for the question above. Q3. Calculate the work done (eV) on an ion of charge +2 when accelerated across 100V. Q4 What voltage is required to accelerate an electron of mass 9.1 x10-31 kg to 10% of the speed of light? c = 3 x 10 8 m/s

18. Excitation by collision *atoms can absorb energy from the incident electron in discrete or quantised amounts without being ionised called excitation energies. The colliding electron having lost its KE does not reach the anode and the current falls The colliding electron causes an electron inside the atom to move from an inner shell to an outer shell. (energy is needed to move the orbiting electron away from the nucleus)

19. Excitation by collision *atoms can absorb energy from the incident electron in discrete or quantised amounts without being ionised called excitation energies. The colliding electron having lost its KE does not reach the anode and the current falls The colliding electron causes an electron inside the atom to move from an inner shell to an outer shell. (energy is needed to move the orbiting electron away from the nucleus)

20. Excitation by collision *atoms can absorb energy from the incident electron in discrete or quantised amounts without being ionised called excitation energies. The colliding electron having lost its KE does not reach the anode and the current falls The colliding electron causes an electron inside the atom to move from an inner shell to an outer shell. (energy is needed to move the orbiting electron away from the nucleus)

21. Excitation by collision *atoms can absorb energy from the incident electron in discrete or quantised amounts without being ionised called excitation energies. The colliding electron having lost its KE does not reach the anode and the current falls The colliding electron causes an electron inside the atom to move from an inner shell to an outer shell. (energy is needed to move the orbiting electron away from the nucleus)

22. Excitation by collision *atoms can absorb energy from the incident electron in discrete or quantised amounts without being ionised called excitation energies. The colliding electron having lost its KE does not reach the anode and the current falls The colliding electron causes an electron inside the atom to move from an inner shell to an outer shell. (energy is needed to move the orbiting electron away from the nucleus)