WAEC Past Questions and Answers - Page 4171

20,851.

lf the frequency of the a.c. circuit illustrated is 500Hz/ π what would be the reactance in the circuit?

A.

0.01Ω

B.

190.91 Ω

C.

200.00 Ω

D.

795.46 Ω

E.

1000.00Ω

Correct answer is C

C1 + C = 2 + 3 = 5μF

Capacitive reactance =
1/2πfc

X =
1/2π x 500 x 5 x 10-6
= 200

20,852.

What is the electric potential at a point distance r from a proton of charge q placed in a medium of permittivity εo?

A.

q2/4πεor2

B.

q/4πεor2

C.

q2/4πεor

D.

qr/4πεo

E.

4πεoq2r

Correct answer is B

No explanation has been provided for this answer.

20,853.

Which of the following substances from the mother's blood diffuses through the placenta into the blood vessels of the feotus?

A.

Carbon dioxide and oxygen

B.

Glycogen and starch

C.

Urea and carbon dioxide

D.

Glucose and oxygen

E.

Digested food and carbon dioxide

Correct answer is D

No explanation has been provided for this answer.

20,854.

Which of the following is not part of the female reproductive system?

A.

Ovary

B.

Seminal vessicle

C.

Uterus

D.

Vagina

E.

Fallopian tube

Correct answer is B

No explanation has been provided for this answer.

20,855.

The diagrams above show lines of force in electric fields. In which of the diagrams would a positive test charge experience the least force as it moves from x to y?

A.

I only

B.

II only

C.

III only

D.

I and II only

E.

II and III only

Correct answer is A

No explanation has been provided for this answer.