Waec Physics 1998 Past Questions and Answers

Question 31:

• WAEC 1998

An astronomical telescope having an objective of focal length 100cm and an eyepiece of focal length 10cm is used in normal adjustment, calculate the separation of the lenses

A. 0.10m
B. 0.90cm
C. 1.10m
D. 1.80m
E. 2.20m

Question 32:

• WAEC 1998

A lantern gives an image of 3m square of a slide 7.62cm square on a screen. If the screen is 10m from the projection lens of the lantern, calculate the focal length of the lens

A. 40.3cm
B. 26.1cm
C. 24.8cm
D. 0.7cm
E. 0.3cm

Question 33:

• WAEC 1998

The intensity of light falling on the film in a camera depend on the i. brightness of the object. ii. diameter of the aperture stop. iii. speed of the shutter. Which of the statements is/are correct/

A. I, ii and iii
B. I and ii only
C. I and ii only
D. Ii and iii only
E. Iii only

Question 34:

• WAEC 1998

the shortest length of the air column in a resonance tube at resonance is 0.12m and the next resonance length is 0.37m. calculate the frequency of vibration given that the speed of sound in air is 340m^-1

A. 1360Hz
B. 694Hz
C. 680Hz
D. 34Hz
E. 340Hz

Question 35:

• WAEC 1998

A sonometer wire under a tension of N10N, produces a frequency of 250Hz when plucked. Keeping the length of the wire constant, the tension is adjusted to produce a new frequency of 350Hz. Calculate the new tension

A. 39.2N
B. 19.6N
C. 14.2N
D. 7.4N
E. 5.1N