In a series R-L-C circuit, R = 10\(\Omega\), \(X_{c}\)= 4\(\Omega\) and \(X_{L}\) = 9\(\Omega\). The impedance of the circuit is
- A. 4.1\(\Omega\)
- B. 5.0\(\Omega\)
- C. 10.8\(\Omega\)
- D. 11.2\(\Omega\)
In which of the following activities is an induction coil not useful?
- A. Investigation of high voltages
- B. Study of electric discharge
- C. Operation of X-ray tubes
- D. A.C. power transmission
Which of the following statements about magnetic lines of force is not correct? They
- A. pass through even non-magnetic materials
- B. run from the north pole to the south pole
- C. are in a state of tension and tend to be shorted
- D. intersect one another
The circuit contains three ammeters A1, A2 and A3 with readings of A2 and A3 shown as indicated in the diagram. Determine the reading of A1.
- A. 2A
- B. 3A
- C. 5A
- D. 8A
Which of the following statements about parallel plate capacitors is/are correct?
I. Capacitance of the capacitor is inversely proportional to the distance between the plates
II. Capacitors can filter a.c signals from d.c
III. Capacitors can store charges
- A. I only
- B. I and II only
- C. II and III only
- D. I, II and III
The diagram above illustrates the wire connections to a three-pin plug. The wires P, Q and R respectively are:
- A. live, neutral and earth
- B. neutral, earth and live
- C. earth, live and neutral
- D. earth, neutral and live
Which of the following statements is not an advantage of an alkaline accumulator?
- A. The electrolyte does not need attention
- B. It can be recharged
- C. It has low internal resistance
- D. It has a much longer life than lead-acid accumulator
A resistor with fixed resistance value is called a
- A. resistance box
- B. standard resistor
- C. shunt resistor
- D. multiplier resistor
The diagram above illustrates a waveform. Determine the number of wavelengths in it
- A. 4
- B. 3\(\frac{1}{2}\)
- C. 2\(\frac{1}{2}\)
- D. 2
A wire of length 400cm is stretched between two fixed points. When plucked, its fundamental frequency is 150Hz. Calculate the speed of the wave produced.
- A. 250\(ms^{-1}\)
- B. 625\(ms^{-1}\)
- C. 1200\(ms^{-1}\)
- D. 1500\(ms^{-1}\)
When the speed of a car is halved, its kinetic energy is
- A. doubled
- B. quartered
- C. halved
- D. quadrupled
In the diagram illustrated a block of mass M is at rest on a plane inclined at an angle \(\theta\) to the horizontal. As \(\theta\) increases, the velocity ratio of the plane
- A. increases
- B. decreases
- C. remain the same
- D. decreases and later increases
The primary of a transformer has 100 turns and its secondary has 200 turns. If the voltage at the primary is 100V, determine the voltage at the secondary.
- A. 50V
- B. 100V
- C. 200V
- D. 400V
Two objects P and Q of masses 100kg and 20kg respectively are 1.2m apart on a horizontal surface. Calculate the net gravitational force acting on Q. \([G= 6.67 \times 10^{-11} Nm^{2}kg^{-2}]\)
- A. \(1.11\times 10^{-7} N\) towards P
- B. \(1.11\times 10^{-7} N\) towards Q
- C. \(9.26\times 10^{-8} N\) towards P
- D. \(9.26\times 10^{-8} N\) towards Q
The diagram above represents a transverse travelling wave. Which two points are 180° out of phase?
- A. A and E
- B. B and D
- C. C and F
- D. D and H
To obtain a virtual, erect and magnified image from a thin converging lens, an object must be placed
- A. between the focus and the lens
- B. at the focus
- C. between the focal length and twice the focal length
- D. beyond twice the focal length
A bar AB is balanced horizontally on two knife edges as illustrated as in the diagram above. Determine the weight of the bar.
- A. 10.0N
- B. 20.0N
- C. 40.0N
- D. 50.0N
A simple barometer is constructed using a liquid \(Q_{1}\) of density 16.2\(g/cm^{3}\). Calculate the least lenth of the tube to be used to measure pressure of 1.5atm. [Density of mercury = 13.6\(g/cm^{3}\), 1atm = 76.0 cm of Mercury]
- A. 1358mm
- B. 957mm
- C. 760mm
- D. 638mm
Which electrical device is illustrated above?
- A. a.c. generator
- B. a.c. motor
- C. d.c. generator
- D. d.c. motor
When two flat plate conductors are arranged in such a way that they possess equal and opposite charges seperated by a dielectric, they form a/an
- A. electroscope
- B. electrophorus
- C. capacitor
- D. cell
The pitch of a note is not affected by
- A. frequency
- B. tension in a vibrating string
- C. mass of a vibrating string
- D. amplitude of sound wave