A particle of charge q and mass m moving with a velocity v enters a uniform magnetic field b in the direction of the field. The force on the particle is
AqvB
BmqvB/m
CmvB/q
DO
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Question 12
waec1991
In which of the following is a stationary wave produced? i. A vibrating turning fork held near the end of a resonance tube closed at one end. ii. A string tightly stretched between two points and plucked at its middle. iii. The tuning fork vibrating in air
Ai only
Bii only
Ci and ii only
Dii and iii only
Ei, ii and iii
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Question 13
waec1991
A man standing 300m away from the wall sounds a whistle. The echo from the wall reaches him 1.8sec. later, calculate the velocity of sound in air
A540.0ms-1
B333.3ms-1
C270.0ms-1
D166.7ms-1
E83.3ms-1
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Question 14
waec1991
Which of the following statements is true of the diagram shown above?
Athe two point, A and B are in phase
Bdistance AB is halgf the wavelength of the wave
CAC and BD are the amplitude of the wave
Dthe two points A and B represents the wave crests
Ethe wave has four crests
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Question 15
waec1991
The sound from a bell in an enclosed jar gradually faints away while the jar is being evacuated. Which of the following explains this observation?
Athe pressue is reduced
Bthe sound waves are pumped out
Cthe waves are absorbed in the inner walls
DThere is no more material medium
Ethe air is disturbed
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Question 16
waec1991
What type of motion does the skin of a talking drum perform when its being struck with the drum stick?
Arandom
Brational
Cvibratory
Dtranslational
Ecircular
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Question 17
waec1991
Which of the following statements about wave is not correct? i. A wavefront is a line which contains all particles whose vibration are in phase. ii. The direction of propagation of a wave is the link drawn parallel to the wavefront. iii. A wavefront is a circle which is common to particles that are in the same state of disturbance
Ai only
Bii only
Ci and ii only
Di and iii only
Eii and iii only
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Question 18
waec1991
Which of the following remains unchanged as light travels from one medium to the other? i. speed. ii. wavelength. iii. frequency.
Ai only
Bii only
Ciii only
Di and ii only
Ei and iii only
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Question 19
waec1991
Which of the following is not a mechanical wave?
Awave propagatd in stretched string
Bwave in closed pipe
Cradio waves
Dwater waves
Esound waves
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Question 20
waec1991
what part of the camera corresponds to the iris of the eye?
Ashutter
Bfilm
Clens
Ddiaphram
Efocusing ring
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Question 21
waec1991
At which of the following distances from the lens should a slide be placed on a slide projector if f is the focal length of the projector length?
Aless than f
Bgreater than f but less than 3f
Cequal to f
Dequal to 2f
Egreater than 2f
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Question 22
waec1991
Which of the following are true of plane-polarised light? i. Plane polarisation of light is the formation of hydrogen bubbles on the particle of light. ii. Plane polarisation of light is the splitting of light into its spectral components iii. A plane polarised light vibrates in one plane. iv. Polarisation of light is characteristic of transverse vibration
Ai and ii only
Bi and iv only
Cii and iii only
Diii and iv only
Ei and iii only.
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Question 23
waec1991
An image which can be formed on a screen is said to be
Avirtual
Bblurred
Cinverted
Derect
Ereal
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Question 24
waec1991
Calculate the refractive index of the material of the glass block shown in the diagram if YZ = 4cm
A0.40
B0.60
C1.50
D1.67
E2.50
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Question 25
waec1991
A ray of light is incident at an angle of 30º on a glass prism of refractive index 1.5. Calculate the angle through which the ray is minimally deviated in the prism. (The medium surrounding the prism is air)
A10.5o
B19.5o
C21.1o
D38.9o
E40.5o
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Question 26
waec1991
In the arrangement illustrated above, Y and B are yellow and blue transparent light filters respectively through the filters is
Ablue
Bred
Cyellow
Dgreen
Eblack
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Question 27
waec1991
Two mirrors are inclined as shown in the diagram. A ray of light RO strikes the arrangement at O and emerges along PO. The emergent ray has been deviated through
A240o
B180o
C120o
D60o
E30o
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Question 28
waec1991
The graph above shows the expansion of water as the temperature increases from 0oC. Which of the following deductions from the graph are true? i. Water has its maximum density at Q. ii. The volume of water is greater at 0oC than at 4oC. iii. The volume of water decreases uniformly when cooled from 100oC. iv. When water solidifies, its volume increases
Ai and ii only
Bi and iii only
Cii and iii only
Di, ii and iii only
Ei, ii and iv only
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Question 29
waec1991
Two forces, whose resultant is 100N are perpendicular to each other. If one of them makes an angle of 60o with the resultant, calculate the magnitude. (Sin 60o = 0.8660, Cos 60o = 0.500)
