WAEC Past Questions and Answers - Page 3228

16,136.

Boyle’s law may be Written as

A.

P1V1= P2V2

B.

V1 = V2 ÷ T1T2

C.

P1T1 = P2T2

D.

P1V1 ÷ T1 = P1V1 ÷ T2

Correct answer is A

Boyle‘s law stats that the volume of a given mass of a gas, at a constant temperature is inversely proportional to us pressure.

Mathematically

V ∝ l/p, v = k/p (where k is constant)

K = VP

Let k = k1

Then, if k = k, V and P = V1P1

V1P1 = V2P2

There is an explanation video available below.

16,137.

If the volume of a gas is recorded as 76cm3 at a temperature of 27°C with a pressure of 800mmHg. What will be the volume of the gas at S.T.P?

A.

36.2cm3

B.

25.7cm3

C.

72.8cm3

D.

24.3cm3

Correct answer is C

General formular of Gas laws

(P1V1) ÷ T1= (P2V2) ÷ T2

P1 = 800mmHg, V, = 76cm3, Tr = 273 + 27 = 300k

P2 = 760mmHg, V2 = ? T2= 273 + 0 = 273  

(800 × 76) ÷ 300 = (760 × V2) ÷ 273

V2 = (300 × 76 × 273) ÷ (300 × 760) = 72.8 cm3

The volume of gas as S.T.P = 72.8 cm3

There is an explanation video available below.

16,138.

An element of nucleon number P and atomic number Q emits an alpha particle from its nucleus. The resultant numbers of the new element formed are respectively

A.

P - 4 and Q + 2

B.

P - 4 and Q - 2

C.

P + 2 and Q + 2

D.

P + 2 and Q - 2

Correct answer is B

No explanation has been provided for this answer.

16,139.

An aluminum foil is placed across a beam of radiation from a radioactive source. Which of the following types of radiation will be stopped by it?

A.

alpha and beta particles

B.

alpha and gamma particles

C.

beta and gamma particles

D.

gamma particles only

Correct answer is A

No explanation has been provided for this answer.

16,140.

Which of the following statements is the major advantage of nuclear fusion over nuclear fission?

A.

nuclear fusion releases more energy

B.

more neutrons are released in fusion than in fission

C.

fussion does not release as much dangerous radiation as fission

D.

fusion reactions occur more readily than fission

Correct answer is C

No explanation has been provided for this answer.