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JAMB Physics Past Questions & Answers - Page 109

542.

Which of the following pairs of light rays shows the widest separation in the spectrum of white light?

A.

Red and blue

B.

Orange and green

C.

Red and indigo

D.

Violet and green

E.

Yellow and red

Correct answer is C

This is called dispersion . A beam of white light passes through a prism and changes into a spectrum of colours.

The spectrum is a band of seven colours which is obtained by splitting of white light by a glass prism. The order of colours from the lower end of spectrum is violet (V), indigo (I), blue (B), green (G), yellow (Y), orange (O), and red (R).

543.

The image is a plane mirror is

A.

inverted, real with a magnificant of 12

B.

inverted, virtual with a magnification of 1

C.

inverted, real with a magnification of 2

D.

upright, virtual with a magnificent of 1

E.

upright, real with a magnification of 2

Correct answer is D

No explanation has been provided for this answer.

544.

A man standing 510m away from a wall sounds a whistle. The echo from the wall reaches him 3s later. Calculate the velocity of sound in air.

A.

170 ms-1

B.

340 ms-1

C.

680 ms-1

D.

765 ms-1

E.

1530 ms-1

Correct answer is B

No explanation has been provided for this answer.

545.

An astronomical telescope which is being used to view a very distant object is said to be in normal adjustment if

A.

the final image is at the near-point

B.

the image formed by the objective is before the focus of the eye piece

C.

the angular magnification is the ratio of the focal length of the eye-piece lens to that of the objective

D.

the foci dl the objective and the eye-piece coincide between the lenses

E.

the distance between the objective lens and the eye-piece is equal to the difference between their focal lengths.

Correct answer is D

No explanation has been provided for this answer.