Waec Physics 2007 Past Questions and Answers

Question 41:

• WAEC 2007

Five 80-W and three 100W are run for 8 hours. If the cost of energy is N5.00 per unit, calculate the cost of running the lamp. [1 unit = 1 kWh]

A. N280.00
B. N28.00
C. N7.20
D. N1.44

Question 42:

• WAEC 2007

Which of the following electromagnetic wave can be detected by its heating effect?

A. Ultraviolet radiation
B. X-rays
C. Gamma rays
D. Infrared radiation

Question 43:

• WAEC 2007

If a gas is excited by high voltage to produce a discharge and the light is examined in a spectrometer

A. An explosion is observed
B. The rainbow colours are seen
C. An emission spectrum is observed
D. Dark lines are observed

Question 44:

• WAEC 2007

The number of protons in an element increased by one after a radioactive decay. The element must have decay by emitting

A. A beta particle
B. An alpha particle
C. A gamma ray
D. A neutron

Question 45:

• WAEC 2007

In a nuclear reactor, chain reactions result from the release of

A. Electrons
B. Photons
C. Neutrons
D. Protons