NECO Physics Past Questions & Answers - Page 53

261.

The falling of light energy on a metal such that electrons are liberated from the metal is called

A.

electron effect

B.

metal electron effect

C.

metal emission

D.

photoelectric effect

E.

photoemission

Correct answer is E

No explanation has been provided for this answer.

262.

An object 3.00m high is placed at a distance of 7.50m from a pin-hole camera. If the image height is 6.00 cm, what is the distance of the film from the pin-hole?

A.

3.75cm

B.

7.50cm

C.

15.00cm

D.

30.00cm

E.

150.00 cm

Correct answer is C

No explanation has been provided for this answer.

263.

The main function of the commutator in a simple d.c. motor is to

A.

enable the armature to rotate freely

B.

increase the flux linking the armature windings

C.

maintain a direct current in the armature

D.

provide uniform magnetic field around the armature

E.

reverse the direction of the current in the armature.

Correct answer is E

No explanation has been provided for this answer.

264.

When an astronomical telescope is in normal adjustment, the focal length of the objective lens is 50cm and that of the eye piece is 5.0cm. What is the distance between the lenses?

A.

10.0cm

B.

30.0cm

C.

45.0cm

D.

55.0cm

E.

250.0cm

Correct answer is D

An astronomical telescope is said to be in NORMAL adjustment when the distance between the objective lens and the eyepiece equals the sum of their focal lengths.

hence,

D = F\(_{e}\) + F\(_{o}\)

= 50cm + 5cm

= 55cm

265.

Given the same amount of beat, a quantity of water will reach a higher temperature in a brass pot than in a clay pot of the same mass because

A.

brass is less dense than clay

B.

clay expands more slowly than brass

C.

clay loses heat faster than brass

D.

the specific heat capacity of brass is higher than that of clay

E.

the specific heat capacity of brass is lower than of clay.

Correct answer is E

No explanation has been provided for this answer.