WAEC Past Questions and Answers - Page 4093

20,461.

The image of an object is located 6cm behind a convex mirror. If its magnification is 0.6, calculate the focal length of the mirror

A.

3.75cm

B.

6.60cm

C.

10.00cm

D.

-15.00cm

Correct answer is D

V = -6cm

M = 0.6cm

Recall m = \(\frac{V}{U}\)

U = \(\frac{V}{M}\)

U = \(\frac{6}{0.6}\)

 U = 10

  \(\frac{1}{U}\) + \(\frac{1}{V}\) = \(\frac{1}{F}\)

 \(\frac{1}{10}\) + \(\frac{1}{-6}\) = \(\frac{1}{F}\)

\(\frac{-4}{60}\) = \(\frac{1}{F}\)

 F = \(\frac{60}{-4}\)

=  -15cm

20,462.

Which of the following is an example of reproductive adaptation?

A.

Succulent stems of a cactus plant

B.

Changing colour of chameleon

C.

Possession of spines by desert plants

D.

Neck colouration in Agama lizard

E.

Leaf-shedding in trees

Correct answer is D

No explanation has been provided for this answer.

20,463.

The air column in a resonance tube is set into resonance by a vibrating tuning fork. The resultant waves in the air column will be

A.

mechanical and transverse

B.

progressive and longitudinal

C.

stationary and transverse

D.

stationary and longitudinal.

Correct answer is D

No explanation has been provided for this answer.

20,464.

The theory that new organs or characteristics develop in organisms when there is a need for them was postulated by

A.

Charles Darwin

B.

Jean Lamarck

C.

Gregor Mendel

D.

Wallace

E.

Louis Pasteur

Correct answer is B

No explanation has been provided for this answer.