Calculate the current in the 3Ω resistor shown in
the diagram above.
A3.0A
B4.0A
C4.3A
D12.0A
E39.0A
View Explanation & Discuss
Question 892
waec1990
Given that the gravitational constant is 7 X 10-11 Nm2kg-2, what is the force of attraction between 106kg mass of lead hanging one metre away from a 103kg mass of iron?
A7 x10-20N
B7 x 10-5N
C7x10-2N
D7x103N
E7x100N
View Explanation & Discuss
Question 893
waec1990
Which of the following pairs of light rays shows the widest separation in the spectrum of white light?
AYellow and red
BOrange and green
CViolet and blue
DBlue and green
ERed and indigo
View Explanation & Discuss
Question 894
waec1990
A simple microscope forms an image twice the size of the object. If the focal length of the lens of the microscope is 20m, how far is the object from the lens?
A10m
B20m
C30m
D40m
E60m
View Explanation & Discuss
Question 895
waec1990
The eye defect illustrated by the diagram above is
Aastigmatism
Blong sightedness
Closs accommodation
Dshort sightedness
Ecolour blindness
View Explanation & Discuss
Question 896
waec1990
The eye defect illustrated by the diagram above is
Aastigmatism
Blong sightedness
Closs accommodation
Dshort sightedness
Ecolour blindness
View Explanation & Discuss
Question 897
waec1990
The diagram above shows an incident ray A, inclined at angle of 50º to the interface CB. The ray OB is found to lie along the surface. What is the refractive index of the medium X with respect to air?
Asin50o/sin40o
Bsin40osin50o
Csin90o/sin50o
Dsin40o/sin90o
Esin90o/sin40o
View Explanation & Discuss
Question 898
waec1990
The diagram above shows an incident ray A, inclined at angle of 50o to the interface CB. The ray OB is found to lie along the surface. What is the refractive index of the medium X with respect to air?
Asin50o/sin40o
Bsin40osin50o
Csin90o/sin50o
Dsin40o/sin90o
Esin90o/sin40o
View Explanation & Discuss
Question 899
waec1990
A parallel beam of light is to be obtained from the headlamp ofa car. At which of the following positions should the source of light be placed from the pole of its spherical minor?
AAt the focal point
BAt the centre of curvature
CBeyond the centre of curvature
DBetween the focal point and the pole
EBetween the focal point and the center of curvature
View Explanation & Discuss
Question 900
waec1990
Where will the image of the object OB shown in the diagram above be located after reflection from the mirror?
AAt F
BBeyond C
CBetween O and P
DBetween P and F
EBetween F and C
View Explanation & Discuss
Question 901
waec1990
A concave mirror of radius of curvature 20cm has a pin placed at 15cm from its pole. What will be the magnification of the image formed?
A4.00
B2.00
C1.33
D1.50
E0.25
View Explanation & Discuss
Question 902
waec1990
A stone is dropped into the middle of a pool of water. Which of the following statements is/are correct? I, Spherical waves are set up in the water. II. The water moves outwards to the sides of the pool. III. Energy is transmitted outwards from the centre of disturbance
AI only
BII only
CIII only
DI and III only
EII and III only.
View Explanation & Discuss
Question 903
waec1990
Which of the following is/are necessary for the production of interference with two wave trains? I. The sources must be close to each other. II The waves must have the same frequency. III. The waves must have the same amplitude. IV. The waves must travel with the speed of light.
AI, II and IV only
BI, II and III only
CI and II only
DII, III and IV only
El, III and IV only
View Explanation & Discuss
Question 904
waec1990
The diagram above represents part of a wave motion in air. If the wave travels with a speed of 300ms-1calculate the frequency of the wave.
A360Hz
B300Hz
C250Hz
D150Hz
E100Hz
View Explanation & Discuss
Question 905
waec1990
Which of the following is/are characteristics of sound? I Pitch II. Loudness III. Quality IV Noise
AI only
BII only
CI and II only
Dl, II and III only
EI, II, III and IV
View Explanation & Discuss
Question 906
waec1990
A tuning fork sounds louder when its stem is pressed against a table top than when held in air because
Aa larger mass of air is set vibrating by the table top
Bthe whole table vibrates in resonance
Cthe whole table has acquired a larger frequency
Dthe fork and table have the same frequency
Ethe amplitude of the vibrating fork is increased.
View Explanation & Discuss
Question 907
waec1990
A bat emits a sound wave at a speed of 1650.0ms-1 and receives the echoes 0.15s later. Calculate the distance of the bat from the reflector
A8.75m
B16.50m
C87.75m
D123.75m
E330.00m
View Explanation & Discuss
Question 908
waec1990
When the direction of vibration of the particles of a medium is perpendicular to the direction of travel of a wave the wave transmitted is known as
Asound wave
Btransverse wave
Clongitudinal wave
Dstationary wave
Emechanical wave
View Explanation & Discuss
Question 909
waec1990
Which of the following is not a suitable method for reducing loss of heat from a piece of hot iron?
AWrapping it in cotton wool
Bpainting it black
CPlacing it in a vacuum
DPlacing it on rubber supports
EKeeping it in a closed wooden box
View Explanation & Discuss
Question 910
waec1990
Heat transfer by convection in a liquid is due to the
Atranslatory motion of the molecules of the liquid
Bincreased vibration of the molecules of the liquid about their mean positions
Cexpansion of the liquid as it is heated
Dlatent heat of vaporization of the liquid
Eability of the liquid to evaporate at all temperatures
