Question 161:

• JAMB 1981

If a source of sound is moving, a stationary listener will hear a sound of different frequency. This is called

A. Doppler effect
B. Resonance
C. Ultra sound
D. Diffraction of sound
E. Rarefaction

Question 162:

• JAMB 1981

Which of the following elements are real magnetic materials?

A. Iron, steel and nickel
B. Copper, steel and iron
C. Lead, iron and brass
D. Glass, lead and steel
E. Stone, air and iron

Question 163:

• JAMB 1981

An inclined plane of angle \(\theta\), acting as a simple machine, has a velocity ratio

A. Sin\(\theta\)
B. \(\frac{1}{\text{sin}\theta}\)
C. Cos\(\theta\)
D. \(\frac{1}{\text{cos}\theta}\)
E. Sin\(\theta cos\theta\)

Question 164:

• JAMB 1981

Heat may be transferred by conduction, convection and radiation. By which of these methods does heat travel through vacuum?

A. Conduction only
B. Convection only
C. Radiation only
D. Non of these methods

Question 165:

• JAMB 1981

Which of the following statements is applicable to a real image formed by a concave mirror? i. it can be observed on a screen ii. it is always inverted and in front of the mirror iii. it only seams to exist IV. it is formed by the actual converging of rays of light

A. I, ii and iii
B. I, ii and iv only
C. I and ii only
D. I and ii only
E. All four statements