Physics Past Questions And Answers
Which of the following statements? i. land and sea breezes are natural convection currents. ii. convection may occur in liquids or gasses but not in solids. iii. the vacuum in a thermos flask prevents heat loss due to convection only.
- A. i and ii only
- B. i and iii only
- C. i and iii only
- D. i, ii, and iii
Calculate the refractive index of the material of the glass block shown in the diagram if YZ = 4cm
- A. 0.40
- B. 0.60
- C. 1.50
- D. 1.67
A straight wire 15cm long, carrying a current of 6.0A is in a uniform field of 0.40T. What is the force on the wire when it is at right angle to the field
- A. 0.46N
- B. 0.35N
- C. 0.36N
- D. 0,24N
A progressive wave is represented by y = 10Sin(1000πt − πx/34) . two layers of the wave separated by 153cm have a phase difference of
- A) 2700
- B) 450
- C) 900
- D) 1800
What is the image distance of an object placed at a distance of 2f from a converging lens of focal length f?
- A. f/4
- B. f/2
- C. f
- D. 2f
The diagram given illustrates the waveform of a note produced by vibrations in an air column of length L. If the speed of sound in air is V, derive an expression for the frequency of the notes
- A. \(\frac{V}{L}\)
- B. \(\frac{5VL}{2}\)
- C. \(\frac{5L}{4V}\)
- D. \(\frac{5V}{4L}\)
The amount of heat needed to raise the temperature of 10kg of Copper by 1K is its
- A. specific heat capacity
- B. latent heat
- C. heat capacity
- D. internal energy
The ratio of the coefficient of linear expansion of two metals âˆ1/âˆ2 is 3:4. If, when heated through the same temperature change, the ratio of the increase in length of the two metals, e1/e2 is 1:2, the ratio of the original lengths l1/l2 is
- A) 8/3
- B) 3/2
- C) 2/3
- D) 3/8
List three magnetic elements that determine the earth’s magnetic field at a point.
View Discussion (0)WAEC 2019 THEORYThe purpose of commutators in a direct current motor is to
- A. reverse the direction of the current after every half rotation
- B. increase the number of rotations per second
- C. enable a uniform couple to act on the coil.
- D. increase the efficiency of the motor.