(a) State the laws of electromagnetic induction
(b) Explain how one of the laws illustrates the principle of conservation of energy
(c)(i) Draw a labelled diagram of a simple d.c. electric motor and explain how it works.
(ii) State two reasons why the efficiency of an electric motor is less than 100%.
(a) Explain what is meant by a magnetic field
(b)(i) Describe an experiment to show that a magnetic field exists around a straight wire carrying current
(ii) Draw a labelled diagram showing the pattern and direction of the magnetic field rroduced around the wire. (Neglect the earth’s magnetic field).
(c) Sketch the magnetic field due to two straight parallel wires carrying current in the same direction. Indicate the neutral point in the field
(d) Explain, with the aid of a labelled diagram, how a delicate magnetic material could be protected from the earth’s magnetic field.
(a) Describe an experiment to show how the frequency of the note emitted by a vibrating string depends on the tension in the string
(b) Draw diagrams showing a vibrating string fixed at both ends emitting (i) fundamental frequency (ii) second overtone indicate the nodes and antinodes on the diagrams
(c) With the aid of a ray diagram show how a virtual image of an object is formed by a (i) concave mirror (ii) converging lens
(a) What is meant by the statement: The specific heat capacity of copper is \(400 J kg^{-1}K^{-1}\)?
(b)(i) Describe an experiment to determine the specific heat capacity of copper using a copper ball.
(ii) State two precautions necessary to obtain accurate results
(iii) A piece of copper ball of mass 20 g at 200°C is placed in a copper calorimeter of mass 60 g containing 50 g of water at 30°C, ignoring heat losses, calculate the final steady temperature of the mixture (Specific heat capacity of water = \(4.2 J g^{-1}K^{-1}\)) (Specific heat capacity of copper = \(0.4 Jg^{-1}K^{-1}\)).
The density of water is 1g\(cm^3\) while that of ice is 0.9\(cm^3\), calculate the volume change when 90g of ice is completely melted
- A. 0\(cm^3\)
- B. 9\(cm^3\)
- C. 10\(cm^3\)
- D. 90\(cm^3\)
- E. 100\(cm^3\)
The density of a body is \(5\times10^3kgm{^-3}\) and it weighs 1N in air. Calculate the apparent weight of the body when totally immersed in water. (Density of water =\(10^3kgm{-3}, g= 10ms^{-2}
- A. 0.02N
- B. 0.08N
- C. 0.20N
- D. 0.80N
- E. 1N
A light wave travels from air into a medium of refractive index 1.54. If the wavelength of the light in air is \(5.9\times10^{-7}\)m, calculate its wavelength in the medium
- A. \(2.5\times10^{-7}\)m
- B. \(3.8\times10^{-7}\)m
- C. \(4.6\times10^{-7}\)m
- D. \(5.2\times10^{-7}\)m
- E. \(6.1\times10^{-7}\)m
Calculate the time taken to heat 2kg of water from 50°C to 100°C in an electric kettle taking 5A, from a 210V supply. (Specific heat capacity of water = 4200\(kg^{-1}K{-1}\)
- A. 2.5 minutes
- B. 5.7 minutes
- C. 6.7 minutes
- D. 7.5 minutes
- E. 9.5 minutes
The pressure of air in a tire is \(22.5Nm^{-2}\) at 27°C. If the air in the tyre heats up to 47°C, calculate the new pressure of the air, assuming that no air leaks out and that the change in volume of the air can be neglected.
- A. \(21.10Nm^{-2}\)
- B. \(24Nm^{-2}\)
- C. \(39.07Nm^{-2}\)
- D. \(45Nm^{-2}\)
- E. \(97.25Nm^{-2}\)
\(500cm^{-3}\) of a gas is collected at 0°C and at a pressure of 72cm of mercury. What is the volume of the the gas at the same temperature and at a pressure of 76cm of the same mercury?
- A. \(\frac{76\times500}{72}cm^3\)
- B. \(\frac{72\times500}{76}cm^3\)
- C. \(\frac{72\times76}{500}cm^3\)
- D. \(\frac{76}{72\times500}cm^3\)
- E. \(\frac{72}{76\times500}cm^3\)
An electric kettle rated 1500W boils away 0.3kg of a liquid at its boiling point every 300s. Calculate the specific latent heat of the vaporisation of the liquid
- A. 1.5 x \(10^6Jkg^-1\)
- B. 1.35 x \(10^6Jkg^-1\)
- C. 1.5 x \(10^5Jkg^-1\)
- D. 4.5 x \(10^2Jkg^-1\)
- E. 3 x \(10^2Jkg^-1\)
500g of water is heated so that its temperature rises from 30°C to 72°C in 7 minutes. calculate the supplied per minute. (Specific heat capacity of water is 4200J\(kg^{-1}K^{-1}\)
- A. 9000J
- B. 12600J
- C. 21000J
- D. 25200J
- E. 88200J
A metal rod of length 40cm at 20°C is heated to a temperature of 45°C. If the new length of the rod is 40.05cm. Calculate its linear expansitivity
- A. 1.2 x \(10^{-5}K{-1}\)
- B. 2.5x \(10^{-5}K{-1}\)
- C. 3.5x \(10^{-5}K{-1}\)
- D. 4.5x \(10^{-5}K{-1}\)
- E. 5x \(10^{-5}K{-1}\)
A body accelerates uniformly from rest at \(2ms^{-2}\). Calculate the velocity after traveling 9m
- A. 36\(ms^{-1}\)
- B. 18\(ms^{-1}\)
- C. 6\(ms^{-1}\)
- D. 4.5\(ms^{-1}\)
- E. 4.24\(ms^{-1}\)
A ball is dropped from a height of 45m above the ground. Calculate the velocity of the ball just before it strikes the ground. (Neglect air resistance and take g as \(10ms^{-2}\)
- A. 21.2\(ms^{-1}\)
- B. 30\(ms^{-1}\)
- C. 300\(ms^{-1}\)
- D. 450\(ms^{-1}\)
- E. 900\(ms^{-1}\)
A cell of e.m.f. 1.5V and internal resistance of 2.5Ω is connected in series with an ammeter of resistance 0.5W and a resistor of resistance of 7.0Ω. Calculate the current in the circuit.
- A. 0.15A
- B. 0.20A
- C. 2.10A
- D. 3A
- E. 6.6A
A note of frequency of 2000Hz has a velocity of \(400ms^{-1}\). What is the wavelength of the note?
- A. 800m
- B. 200m
- C. 5m
- D. 2m
- E. 0.2m
The wave function of a metal is 8.0 x \(10^{-19}\)J. Calculate the wavelength of its threshold frequency. (Speed of light in a vacuum = 3 x \(10^8ms^{-1}, Planck’s constant = 6.6 \times 10^{-34}\)Js)
- A. 0.8 x \(10^{-7}\)m
- B. 1 x \(10^{-7}\)m
- C. 2.3 x \(10^{-7}\)m
- D. 3.8 x \(10^{-7}\)m
- E. 12.4 x \(10^{-7}\)m
The nucleon number and the proton number of a neutral atom of an element are 238 and 92 respectively. What is the number of neutrons in the atom?
- A. 330
- B. 238
- C. 146
- D. 119
- E. 73
In 24 days a radioactive isotope decreases in mass from 64g to 2g. What is the half life of the radioactive material
- A. 0.75 days
- B. 2.58 days
- C. 4 days
- D. 4.80 days
- E. 6 days
When an atom loses or gains a charge, it becomes an
- A. ion
- B. an electron
- C. a neutron
- D. a proton
- E. a deuteron