Calculate the reactance of the inductor in the circuit diagram shown above [\(\pi = \frac{22}{7}\)]
- A. 132\(\Omega\)
- B. 214\(\Omega\)
- C. 264\(\Omega\)
- D. 269\(\Omega\)
In the circuit diagram above. Calculate the energy stored in the inductor at resonance
- A. 0.100J
- B. 0.050J
- C. 0.010J
- D. 0.005J
The material used for constructing the core of an electromagnet is
- A. iron
- B. carbon
- C. copper
- D. steel
Which of the following statements about magnetic lines of force is not correct?
- A. a magnnetic line of force is an imaginary line which the north pole of a magnet would describe if it is free to moves
- B. magnetic lines of force do not cross one another
- C. magnetic lines of force are closely packed together at neutral point
- D. the presence of magnetic lines of force in a region indicates the presence of a magnetic field
The Earth’s magnetic equator passes through Jos in Nigeria. At Jos. the
- A. angle of variation is zero
- B. magnetic declination is 90o
- C. angle of dip is zero
- D. horizontal component of the Earth's magnetic field is zero
An electric bulb is rated 60W, 220V. Calculate the resistance of its filament when it is operating normally
- A. 296.7\(\Omega\)
- B. 400.0\(\Omega\)
- C. 512.2\(\Omega\)
- D. 806.7\(\Omega\)
Three identical lamps each power 100W are connected in parallel across a potential difference of 250V. Calculate the current in the circuit
- A. 7.5A
- B. 2.5A
- C. 1.2A
- D. 0.8A
What is the total energy stored by the capacitors?
- A. 2.0 x 10-4J
- B. 1.0 x 10-4J
- C. 9.0 x 10-2J
- D. 1.0 x 10-2J
What is the effective capacitance in the circuit?
- A. 2\(\mu F\)
- B. 6\(\mu F\)
- C. 18\(\mu F\)
- D. 216\(\mu F\)
As the plates of a charged variable capacitor are moved closer together, the potential difference between them
- A. increased
- B. decrease
- C. remains the same
- D. is doubled
The magnitude of the gravitational force between two particles 0.10m apart is 10N. If the distance between them is increased to 0.20m, calculate the magnitude of the new force
- A. 40.0N
- B. 20.0N
- C. 5.0N
- D. 2.5N
If the frequency of the tuning fork at resonance is 256Hz, calculate the frequency of vibration of the wire when the tension in he wire is increased to 196N
- A. 130.6Hz
- B. 182.9Hz
- C. 358.4Hz
- D. 501.8Hz
The diagram above shows the wire of a sonometer box set into resonance by a vibrating tuning fork of frequency f, when the wire is stretched by a tension T, the resonating length of the wire is I while the wavelength of the sound produced is \(\lambda\). Which of the following statements about the frequency of vibration of the wire is not correct?
- A. proportional to the mass per unit length of the wire
- B. equal to the frequency of the tuning fork
- C. inversely proportional to the length of the wire
- D. proportional to the sqare root of the tension
The diagram above shows the wire of a sonometer box set into resonance by a vibrating tuning fork of frequency f, when the wire is stretched by a tension T, the resonating length of the wire is I while the wavelength of the sound produced is \(\lambda\). Which of the following statements is not correct? The wave produced on the wire is
- A. stationary and lonitudinal
- B. stationary and mechanical
- C. mechanical and longitudinal
- D. progessive and transverse
Which of the following statements about sound is correct?
- A. when sound travels from air to a denser medium, it is refracted away from the normal at the point of incidence
- B. sound travels faster in air than in water
- C. the wavelength of sound changes when it travels from to water
- D. the frequency of it travels from air to water
Dispersion of white light by a glass prism occurs because
- A. white light consist of a mixture of seven different colour
- B. the refractive index of glass is different from each constituent colour of white light
- C. the speed of each colour of light in the glass is proportional to the refractive index of glass for each colour
- D. the speed of each colour of light in the glass is proportional to the angle of refraction in he prism
A piece of cloth appears green in sunlight. When held in red light, it will appear
- A. green
- B. blue
- C. red
- D. black
An object is placed 20cm from a lens. If an image is formed on a screen 260cm away from the lens, calculate the magnification of the image
- A. 28
- B. 26
- C. 24
- D. 13
Convex spherical mirrors are preferred to plane mirrors as driving mirrors because
- A. the image produce is upright and clearly visible
- B. it provides a wider field of view
- C. the image produce is errect and diminished
- D. the image produced is not laterally inverted
An incident ray is reflected normally by a plane mirror onto a screen where it forms a bright spot. The mirror and screen are parallel and 1m apart. If the mirror is rotated through 5o, calculate the displacement of the spot
- A. 8.7cm
- B. 10.0cm
- C. 15.4cm
- D. 17.6cm
Surface waves travelling in deep water at 15ms-1 are incident at a shallow water boundary. If the angles of incidence and refraction are 45o and 30o respectively. Calculate the speed of the waves in shallow water
- A. 8.1ms-1
- B. 10.0ms-1
- C. 10.6ms-1
- D. 22.5ms-1