JAMB Physics Past Questions & Answers - Page 335

1,671.

If a reverse-biased voltage is applied across a p-n junction, the depletion layer width is

A.

increased

B.

decreased

C.

constant

D.

halved

Correct answer is B

No explanation has been provided for this answer.

1,672.

The p-n junction diodes can act as rectifiers because they

A.

conduct current when forward-biased

B.

conduct current when reverse-biased

C.

block current when forward-biased

D.

conduct current in both directions

Correct answer is A

No explanation has been provided for this answer.

1,673.

A piece of radioactive material contains 1000 atmos. If its half -life is 20seconds, the time taken for 125 atoms to remain is

A.

20 seconds

B.

40 seconds

C.

80 seconds

D.

60 seconds

Correct answer is D

1000 → 500 → 250 → 125

20 + 20 + 20 = 60s

1,674.

Which of the following CANNOT be deflected by both electric and magnetic fields?

A.

Gamma rays

B.

Alpha particles

C.

Wave particles

D.

Beta particles

Correct answer is A

No explanation has been provided for this answer.

1,675.

The process of detecting a pin mistakenly swallowed by a child is X-ray

A.

Diagnosis

B.

Therapy

C.

Crystallography

D.

Mammography

Correct answer is A

No explanation has been provided for this answer.