WAEC Physics Past Questions & Answers - Page 193

961.

A nitrogen nucleus bombarded with an alpha particle produces an oxygen nucleus and a proton. The nuclear reaction for this process is \(^4_2H + ^{14}_2N \to ^{17}_{8}O + ^1_1H + Q\). Which of the following statements about the reaction is not correct?

A.

the bombardment results into a nucleus with greater proton number

B.

it is an induced nuclear reaction

C.

it is a natural radioactive decay

D.

the sum of the final nucleon numbers

Correct answer is B

This is an example of artificial decay.

Induced radioactivity, also called artificial radioactivity or man-made radioactivity, is the process of using radiation to make a previously stable material radioactive.

963.

Production of x-ray tube begins with

A.

photo electric emission

B.

collision of electrons

C.

thermionic emission

D.

field emission of electrons

Correct answer is D

No explanation has been provided for this answer.

965.

Calculate the reactance of the inductor in the circuit diagram shown above [\(\pi = \frac{22}{7}\)]

A.

132\(\Omega\)

B.

214\(\Omega\)

C.

264\(\Omega\)

D.

269\(\Omega\)

Correct answer is C

\(X_L = 2 \pi fL = 2 \times \pi \times 60 \times 0.7 = 264\Omega \)