JAMB Physics Past Questions & Answers - Page 363

1,811.

Which of the following is a property of steel?

A.

it cannot retain its magnetism longer than iron

B.

it can be used for making temporary magnets

C.

it can be used for making permanent magnets

D.

it can easily be magnetized and demagnetized

Correct answer is C

Steel is not easily magnetized and dismagnetized

1,812.

The eclipse of the sun occurs when the

A.

moon is between the sun and the earth

B.

earth is between the sun and the moon

C.

moon is not completely hidden in the earth's shadow

D.

moon's umbra falls on some part of the earth

Correct answer is A

Eclipse of the sun occurs when the moon which is opaque objects between the sun and the earth

1,813.

A certain far - sighted person cannot see object that are closer to the eye than 50 cm clearly. Determine the power of the converging lens which will enable him to see at 25 cm

A.

0.06 D

B.

0.02 D

C.

0.03 D

D.

0.04 D

E.

no option is correct

Correct answer is B

No explanation has been provided for this answer.

1,815.

When a red rose flower is observed in blue light, what colour does the observer see?

A.

Red

B.

Blue

C.

Magenta

D.

yellow

E.

No correct option

Correct answer is E

The colour which an object presents to the eye is the colour of light it reflects. Red rose flower will therefore absorb any other colour and reflect red. Therefore when viewed in blue light, it has no colur to reflect and will therefore appear black. Although mixture of red light and blue light = magenta .