## Physics 2019 Past Question | WAEC Study the following past questions and answers for JAMBWAEC  NECO and Post-JAMB. Get prepared with official past questions and answers for upcoming examinations.

16. A small amount of air is introduced into the vacuum above the mercury in a mercury barometer tube. The mercury level goes down because the air molecules

• A. heat the mercury and make it expand
• B. increase the pressure above the mercury.
• C. cool the mercury and make it contract.
• D. decrease the pressure above the mercury

17. Calculate the quantity of heat needed to change the temperature of 60g of ice at 0 °C to 80 °C. [specific latent heat of fusion of ice= 3.36 x 105Jkg−1specific heat capacity of water 4.2 x 103 J kg−1]

• A. 4.80 kJ
• B. 20.16 kJ
• C. 40.32 kJ
• D. 22.17 kJ

18. The wire of a platinum resistance thermometer has d resistance of 3.5Ωat 0 °C and 10.52Ωat 100°C. Calculate the temperature of the wire when its resistance is 7.5Ω.

• A. 78 °C
• B. 25 oC
• C. 30oC
• D. 57 oC

19. A transverse pulse of frequency 9 Hz traves 4.5m in 0.6 s. Calculate the wavelength of the pulse.

• A. 3.33 m
• B. 0.30 m
• C. 0.83 m
• D. 1.20 m

20. In which of the following media is the speed of sound the least?

• A. Air
• B. Brass
• C. Water
• D. Wood

21. Which of the following characteristics of waves can a ripple tank be used to demonstrate?
Reflection
II. Refraction
III. Diffraction

• A. I, II and Ill
• B. ll and ll only
• C. l and lII only
• D. I and II only

22. Which of the following graphs gives the correct relationship between energy and mass when mass is converted to energy?

• A. A
• B. B
• C. C
• D. D

23. An 800 kg car moving at 80 km hr−1 collides with a 1200 kg car moving at 40 km hr−1in the same direction. If the cars stick together, calculate their common velocity.

• A. 60 km hr−1
• B. 8 km hr−1
• C. 40 km hr−1
• D. 56 km hr−1

24. The mass of a load is doubled while the force acting on it is halved. The resulting acceleration of the load is

• B. quartered
• C. halved
• D. doubled

25. The maximum and minimum thermometer reads the

• A. the maximum temperature during the day and the minimum temperature at night at all times.
• B.  the maximum temperature at night and minimum temperature during the day from the last reset
• B. the maximum temperature at night and minimum temperature during the day at all times
• D. the maximum temperature during the day and minimum temperature at night from the last reset

26. An a.c. the generator can be converted to a d.c. generator by replacing the

• A. commutator with an armature
• B. armature with a commutator
• C. commutator with slip rings
• D. slip rings with a commutator

27. Which of the following statements is the correct reason for using soft iron in making the armature or an electric bell?

• A. It is a diamagnetic material
• B. It loses its magnetism readily
• C. It is not easily magnetized
• D. It retains its magnetism for a long time

28. The diagram above illustrates a meter bridge circuit under balanced condition. Determine the value of x.

• A. 71.4 cm
• B. 10.0 cm
• C. 28.6 cm
• D. 57.2 cm

29. Which of the following devices is used for storing electric charges?

• A. Transformer
• B. Ammeter
• C. Potentiometer
• D. Capacitor

30. An electron of mass 9.1 x 10−31kg moves with a speed of 2.0 x 106ms−1round the nucleus of an atom in a Circular path of radius 6.1 x 1011 Determine the angular speed of the electron.

• A. 3.28 x 1016 rad s−1
• B. 8.55 x 103 rad s−1
• C. 9.11 x 1013 rad s−1
• D. 5.22 x 1015 rad s−1

## All Subjects

Subscribe
Notify of 