Waec Physics Past Questions For Year 1992

Question 36

A negatively charged rod is brought near the cap of a gold-leaf electroscope. The cap is earthed momentarily while the rod is near to it. The rod is then removed. Which of the following is correct?

waec 1992

• A. The cap will be positively charged and the negatively charged leaves will diverge
• B. The cap will be negatively charged and the positively charged leaves will diverge
• C. The cap and the leaves will be positively charged
• D. The cap and the leaves will be negatively charged.
• E. The leaves will not diverge because the cap has been earthed.

Question 37

The diagram above shows the magnetic field around a bar magnet which has its N-pole pointing north. The neutral points in the field are likely to occur at

waec 1992

• A. 1 and 2
• B. 3 and 4
• C. 5 and 6
• D. 7 and 8
• E. 9 and 10

Question 38

A pipe closed at one end is 1.0m long. The air in the pipe is set into vibration and a fundamental note of frequency 85Hz is produced. Calculate the velocity of sound in the air. (Neglect end correction).

waec 1992

• A. 340.0ms^-1
• B. 33Oms^-1
• C. 170ms^-1
• D. 85.0ms^-1
• E. 42.5ms^-1

Question 39

Which of the following statements is not true?

waec 1992

• A. Musical notes consist of the combination of sounds of regular frequency
• B. The combination of overtones produced by an instrument determines the quality of the sound
• C. the loudness of sound is determined by its frequency
• D. the pitch of a note depends on the frequency of vibration of the source
• E. Noise can be produced by a combination of sounds of irregular frequency

Question 40

Which of the following waves are longitudinal waves? l. Ripples on the surface of water II. Waves produced by a tuning fork vibrating in air III. Light waves

IV. Waves produced by a flute

waec 1992

• A. I and II only
• B. I and III only
• C. II and III only
• D. II and IV only
• E. III and IV only