AS AQA Phys Unit 1 (4)

Created by: Jessica Parkes
Created on: 28-03-13 12:55

An isolated zinc plate with a neutral charge is exposed to high-frequency U.V. light. State and explain the effect of the U.V. light on the charge of the plate. (2 marks)

The plate becomes positively charged (1) Negative electrons in the metal absorb energy from the U.V. light and leave the surface (1)

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Why does photoelectric emission from a metal surface only occur when incident radiation exceeds a certain threshold value? (2 marks)

An electron must gain a certain amount of energy before it can leave the surface of a metal (1) If the energy carried by each photon is less than this work function energy, no electrons will be emitted (1)

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What does the maximum value of kinetic energy an electron can have increase with and what doesn't affect the value? (2 marks)

Maximum kinetic energy of an electron increases with the frequency of radiation (1) it is unaffected by the intesity of radiation (1)

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For an electron which has accelerated through a potential difference of 12.1V, how much kinetic energy has it gained in eV (electronvolts) and joules? (2 marks) -use Data and Formulae Booklet

The electron would have gained 12.1eV (1) or 1.9*10^-18 J (1)

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What is meant by excitation of an atom? (1 mark)

The movement of an electron from a lower energy level to a higher energy level by absorbing energy (1)

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How is energy released during the de-excitation of an atom? (2 marks)

Energy is released in the form of a photon (1) equal to the difference between the energy levels involved (1)

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Other cards in this set

Card 2

Front

Why does photoelectric emission from a metal surface only occur when incident radiation exceeds a certain threshold value? (2 marks)

Back

Card 3

Front

What does the maximum value of kinetic energy an electron can have increase with and what doesn't affect the value? (2 marks)

Back

Card 4

Front

For an electron which has accelerated through a potential difference of 12.1V, how much kinetic energy has it gained in eV (electronvolts) and joules? (2 marks) -use Data and Formulae Booklet

Back

Card 5

Front

What is meant by excitation of an atom? (1 mark)

Back

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AS AQA Phys Unit 1 (4)