Waec Physics 2004 Past Questions and Answers

Question 46:

• WAEC 2004

The main function of the mouth piece of a telephone is that it converts sound energy to

A. Mechanical energy
B. Electrical energy
C. Chemical energy
D. Thermal energy

Question 47:

• WAEC 2004

An atom is normally electrically neutral because the

A. Number of electrons is equal to the number of protons
B. Number of electrons is equal to the number of neutrons
C. Number of protons is equal to the number of neutrons
D. Electrons of the atom are buried deeply in the nucleus

Question 48:

• WAEC 2004

In which of the following devices is the principle of photoelectric effect not applicable?

A. Close-circuit television camera
B. Burglar alarm
C. Solar cells
D. Periscope

Question 49:

• WAEC 2004

Which of the following statements about X-rays is not correct? They

A. Are electromagnetic waves
B. Can be used to study crystal lattice
C. Can destroy living cells
D. Are produced from the nucleus of an atom

Question 50:

• WAEC 2004

A radioactive substance has a half-life of 3 days. If a mass of 1.55g of this substance is left after decaying for 15 days, determine the original value of the mass

A. 49.6g
B. 37.2g
C. 24.8g
D. 12.4g