PHYA1_Rev_3_Q
PHYA1- Rev 3 78 minutes 75 marks Page 1 of 12 Q1. Columns A and B show some of the results from an experiment in which the current I through a component X was measured for various values of the potential difference V applied across it. (a) column A column B column C column D potential difference V / V current I/ mA (V – 0.55) / V In (I / mA) 0.70 12.5 0.75 17.0 0.80 22.0 0.85 29.0 0.90 39.0 0.95 51.5 Draw a diagram of a circuit which could have been used to obtain these results. (2) (b) (i) Calculate the resistance of X when the potential difference is 0.70 V. ............................................................................................................. ............................................................................................................. (ii) By considering one other value of potential difference, explain whether or not X is an ohmic conductor. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (3) Page 2 of 12 (c) It is suggested that for potential differences greater than 0.55 V, the current voltage relationship for X is of the form. I = A ek(V–0.55) where A and k are constants. (i) Complete column C and column D in the table above (ii) Plot a graph of 1n (I /mA ) on the y-axis against (V – 0.55) on the x-axis. (Allow one sheet of graph paper) (iii) Use your graph to determine the constants k and A. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (iv) On the basis of your graph, discuss the validity of the above relationship. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (10) (Total 15 marks) Q2. (a) A neutrino may interact with a neutron in the following way ve + n (i) p + e–. Name the fundamental force responsible for this interaction. ............................................................................................................. Page 3 of 12 (ii) Complete the Feynman diagram for this interaction and label all the particles involved. (3) (b) The neutral kaon, which is a meson of strangeness +1, may decay in the following way π+ + π–. K° (i) Apart from conservation of energy and momentum, state two other conservation laws obeyed by this decay and one conservation law which is not obeyed. ............................................................... conservation law is obeyed ............................................................... conservation law is obeyed ......................................................... conservation law is not obeyed (ii) Deduce the quark composition of all the particles involved in the K° decay. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. K° ......................................................... π+ .......................................................... π– .......................................................... (6) (Total 9 marks) Q3. (a) (i) Explain the meaning of the term work function of a metal. ............................................................................................................. ............................................................................................................. ............................................................................................................. Page 4 of 12 (ii) State what you would need to change in an experiment to investigate the effect of the work function on the photoelectric effect. ............................................................................................................. (3) (b) Experiments based on the photoelectric effect support the particle theory of light. State one conclusion drawn from these experiments and explain how it supports the particle theory. You may be awarded marks for the quality of written communication in your answer. ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... (2) (c) Monochromatic light of wavelength 4.80 × 10–7 m falls onto a metal surface which has a work function of 1.20 × 10–19 J. Calculate (i) the energy, in J, of a single photon of this light, ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (ii) the maximum kinetic energy, in J, of an electron emitted from the surface. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (5) (Total 10 marks) Page 5 of 12 Q4. The diagram below shows an arrangement of resistors. (a) Calculate the total resistance between terminals A and B. answer = ................................................... Ω (2) (b) A potential difference is applied between the two terminals, A and B, and the power dissipated in each of the 400 Ω resistors is 1.0 W. (i) Calculate the potential difference across the 400 Ω resistors. answer = ................................................... V (ii) Calculate the current through the 25 Ω resistor. answer = .................................................... A Page 6 of 12 (iii) Calculate the potential difference applied to terminals A and B. answer = ................................................... V (6) (Total 8 marks) Q5. The diagram shows four energy levels of an atom not drawn to scale. (a) (i) Explain how this atom emits a line spectrum following excitation. You may be awarded marks for the quality of written communication in your answer. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (ii) The longest wavelength of emitted radiation is produced by a transition between which two levels? ............................................................................................................. (iii) Draw on the diagram two vertical arrows between levels to indicate two different transitions that result in emitted radiation of the same frequency. (4) Page 7 of 12 (b) In its ground state the atom absorbs 2.3 × 10–19 J of energy from a collision with an electron. (i) Calculate all the possible frequencies of radiation that the atom may subsequently emit. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (ii) How much energy, in eV, would be required to ionise the atom in its ground state? ............................................................................................................. ............................................................................................................. (5) (Total 9 marks) Q6. (a) How many protons, neutrons and electrons are there in an atom of ? ....................................... protons ....................................... neutrons ....................................... electrons (2) (b) The atom loses two electrons. For the ion formed; (i) calculate its charge in C, ............................................................................................................. (ii) state the number of nucleons it contains, ............................................................................................................. Page 8 of 12 (iii) calculate the ratio in C kg–1. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. (4) (Total 6 marks) A car battery has an emf of 12 V and an internal resistance of 5.0 × 10–3 Ω. Q7. (a) (i) Explain what is meant by the emf of the battery. ............................................................................................................. ............................................................................................................. (1) (ii) Explain what is meant by the internal resistance of the battery. ............................................................................................................. ............................................................................................................. (1) (b) The battery is used to provide the starting motor of a car with a current of 800 A. (i) Calculate the potential difference across the terminals of the battery. answer = ................................................... V (2) (ii) Calculate the rate of dissipation of energy due to its internal resistance stating an appropriate unit. answer = ...................................................... (3) Page 9 of 12 (c) State and explain the effect of attempting to use a battery with a much higher internal resistance to start the car. ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... (2) (Total 9 marks) Q8. (a) Some materials exhibit the property of superconductivity under certain conditions. • State what is meant by superconductivity. • Explain the required conditions for the material to become superconducting. ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... (3) (b) The diagram below shows the cross–section of a cable consisting of parallel filaments that can be made superconducting, embedded in a cylinder of copper. (i) The cross–sectional area of the copper in the cable is 2.28 × 10–7 m 2. The resistance of the copper in a 1.0 m length of the cable is 0.075 Ω. Calculate the resistivity of the copper, stating an appropriate unit. answer = ...................................................... (3) Page 10 of 12 (ii) State and explain what happens to the resistance of the cable when the embedded filaments of wire are made superconducting. ............................................................................................................. ............................................................................................................. ............................................................................................................. (3) (Total 9 marks) Page 11 of 12 Page 12 of 12
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