The electrons in a cathode-ray tube are produced by?
- A. heating a metal filament.
- B. ionization of the air.
- C. applying a magnetic field to the y-plates.
- D. applying an electric field to the x-plates.
Which of the following statements is not a characteristic of a plane progressive wave?
- A. Energy travels out through the medium
- B. Neighboring points along the profile possess different amplitudes
- C. Neighboring points along the profile possess the same amplitude
- D. Neighboring particles vibrate with different phase
A stone is thrown horizontally with initial velocity 15m/s from a tower 20 m high. How long does it take to reach the ground? [g= 10m/s\(^2\)
- A. 2s
- B. 4s
- C. 5s
- D. 1s
An ice cube has mass of 20 g at 5°C. Calculate the energy required to raise its temperature to 0°C. [Specific heat capacity of ice = 2.1 J/g°c]
- A. 105 J
- B. 100 J
- C. 42 J
- D. 210 J
The following statements about a loudspeaker are correct except?
- A. its contains a permanent magnet.
- B. sound signal converted to varying current signal enters the speech coil.
- C. the current in the speech coil creates a magnetic force on the coil.
- D. the magnetic force on the speech coil is uni-directional.
A radioactive material has a half-life of 1.0 hour If 200.0 g of it was present at 6 a.m. on a certain day, how many grams will have decayed by 9 a.m. on the same day?
- A. 175.0 g
- B. 150.0 g
- C. 100.0 g
- D. 187.5 g
An electric circuit consists of a resistor. a battery and a key. If the voltage of the battery is increased, there Would be an increase in the?
- A. current and resistance only.
- B. current resistance and temperature.
- C. current and temperature only.
- D. resistance and temperature only
A force of 10 N, acting continuously, increases the kinetic energy of an object from 20.J to 60 J. Find the distance moved by the object.
- A. 200m
- B. 40m
- C. 4m
- D. 400m
A rotating disc contains a set of holes in a circle. An air jet is directed onto the holes and a note of frequency 480 Hz is produced. If the number of holes is 20, calculate the speed of rotation of the disc.
- A. 10 rev/s
- B. 20 rev/s
- C. 24 rev/s
- D. 8 rev/s.
A man weighing 200 N runs up a staircase in 5s. If the height of the staircase is 9 m, calculate the power of the man.
- A. 1000 W
- B. 360 W
- C. 40 W
- D. 1800 W
Which of the following statements best describes the particles in a solid at room temperature? They are
- A. far apart and moving randomly.
- B. close together and vibrating.
- C. close together and stationary.
- D. close together and moving randomly.
A wire of cross-sectional area 2π * 10\(^-{8}\) m\(2\) and resistivity 1.1 x 10\(^-{8}\) Ω m, has a resistance of 21Ω.
Calculate the length of the wire. [π=22/7]
- A. 180 m
- B. 140 m
- C. 120 m
- D. 240 m
In the diagram above, a bulb is lit by drawing 2.0A from 440V a.c. source. Calculate the cost of keeping the bulb on for two days at $0.40 per kilowatt-hour .
- A. $16.90
- B. $84.48
- C. $1690.00
- D. $8.48
An electric pressing iron is connected to the mains using an insulated wire. wire becomes very hot.
The heat generated in the wire can be minimized by replacing the wire with one of?
- A. thinner insulation.
- B. greater diameter.
- C. smaller diameter.
- D. thicker insulation.
Which of the arrangements of radiations below shows decreasing order of wavelengths?
- A. X-rays> radio waves > infrared radiations
- B. Radio waves> infrared radiations > X-rays
- C. Infrared radiations > radio waves > X-rays
- D. X-rays> infrared radiations > radio waves
The components of vectors Q and R are (-3.0, 5.5) and (9.2, 4.4) respectively. Determine the components of Q + R.
- A. (3.7, 7.4)
- B. (6.2, 9.9)
- C. (2.5, -4 .8).
- D. (14.7, 1.4)
Which of the following curved surfaces will produce a real image? I. Concave mirror II. Convex mirror III. Diverging lens IV. Converging lens
- A. I and III only
- B. I, II and IV only
- C. II, III and V only
- D. II and IV only
Determine the speed of the wave.
- A. 64 cm/s
- B. 32 cm/s
- C. 24 cm/s
- D. 72 cm/s
The sketched graph above represents a progressive wave moving from the left to the right. The period of the wave is 0.125s.
Determine the values of the amplitude and wavelength, respectively, of the wave.
- A. 8 cm; 27 cm
- B. 8 cm; 9 cm
- C. 4 cm; 9 cm
- D. 16 cm; 27 cm
Which of the following statements about the universal gravitational constant, G, is true?
- A. It is fundamental quantity.
- B. It has dimension M-¹L³T-².
- C. Its S.I. unit is N m\(^2\)kg
- D. It is a vector quantity
A current of 2A passes through a wire of resistance 4Ω for 3 minutes. Calculate the energy lost.
- A. 960J
- B. 1440J
- C. 2880J
- D. 48J