WAEC Past Questions and Answers - Page 4121

20,601.

One major difference between osmosis and diffusion is that diffusion

A.

does not need a semipermeable membrane

B.

does not take place in living tissues

C.

takes place only in a liquid medium

D.

takes place only in a gaseous medium

E.

cannot be demonstrated experimentally

Correct answer is A

No explanation has been provided for this answer.

20,602.

A platinum-resistance thermometer has a resistance of 5Ω at 0°C and 9Ω at l00°C. Assuming that resistance changes uniformly with temperature, calculate the resistance of the thermometer when the temperature is 45°C.

A.

13.9 Ω

B.

8.9 Ω

C.

6.8 Ω

D.

3.2 Ω

E.

1.8 Ω

Correct answer is C

\(\frac{\theta}{100} = \frac{R_ {\theta} - R_0}{R_{100} - R_0}\)

\(\frac{45}{100} = \frac{R_{\theta} - 5}{9 - 5}\)

\(45 \times 4 = 100(R_{\theta} - 5)\)

\(180 = 100R_{\theta} - 500\)

\(180 + 500 = 100R_{\theta}\)

\(R_{\theta} = \frac{680}{100}\)

\(R_{\theta} = 6.8 \Omega\)

20,603.

Which of the following is not an organ?

A.

Hair

B.

Tongue

C.

Rhizome

D.

Corn

E.

Heart

Correct answer is A

No explanation has been provided for this answer.

20,604.

Which of the following organisms exhibits both plant and animal characteristics?

A.

Amoeba

B.

Spirogyra

C.

Mucor

D.

Euglena

E.

Moss

Correct answer is D

No explanation has been provided for this answer.

20,605.

Two simple pendula x and y make 400 and 500 oscillations respectively in equal time. If the period of oscillation of x is 1.5 seconds, what is the period of oscillation of y?

A.

0.53s

B.

0.83s

C.

1.20s

D.

1.50s

E.

1.88s

Correct answer is C

where f = \(\frac{oscillations}{time}\)

period = 1/ f or \(\frac{time}{oscillations}\)

For pendulum x:

where period = 1.5 and oscillation = 400

time = oscillations X 1.5 = 600s

For pendulum y:

\(\frac{time}{oscillations}\) → 600/500

period for y = 1.2s

period =