Question 506:

• JAMB 1988

Which of the following phenomena explains the formation of a mirage? i. Reflection ii. Refraction iii. Diffraction

A. I and ii only
B. Ii and iii only
C. I and iii only
D. I, ii, and iii only

Question 507:

• JAMB 1988

When white light is dispersed by a spectrometer, the component having the shortest wavelength is

A. Orange
B. Green
C. Violet
D. Red

Question 508:

• JAMB 1988

Which of the following statement is TRUE of ultraviolet, visible and infra-red rays?

A. They are all electromagnetic waves with the same wavelength
B. Ultra-violet rays have shorter wavelengths than infra-red rays and produce flourescence
C. Infrared rays have shorter wavelength than visible light and produce the sensation of heat
D. The wavelenghts increase in the sequence: visible, ultra-violet, infra-red

Question 509:

• JAMB 1988

A spectrum of sunlight is said to be impure when

A. It is made of only three colours
B. It has no red colour in it
C. The different colours in it overlap
D. It does not contain white light

Question 510:

• JAMB 1988

A cell of internal resistance 2 ohms supplies current to a 6 ohms resistor. The efficiency of the cell is

A. 12.0%
B. 25.0%
C. 33.3%
D. 75.0%