1998 - JAMB Physics Past Questions and Answers - page 3
21
A vapour is said to be saturated when
A
more molecules return to the liquid than the amount that left it
B
a dynamic equilibrium exists between the molecules of the liquid and the vapour molecules at a given temperature
C
the vapour pressure is equal to the atmospheric pressure
D
all molecules are moving with the same speed in all directions at a given temperature
correct option: b
Users' Answers & Comments22
One valid assumption of the kinetic theory of gasses is the
A
the molecules of a gas are constantly in a state of motion and the number of collision remains constant
B
the number of molecule of gas increases with increasing pressure
C
as the temperature increases, the number of collision made by the gas molecule remains constant
D
the molecules of gas are all identical and are very small in size
correct option: d
Users' Answers & Comments23
The physical properties of sound waves can best be described by
A
reflection and diffraction
B
polarization and reflection
C
polarization and diffraction
D
polarization and refraction
correct option: a
Users' Answers & Comments24
In a closed organ pipe producing a musical note, an antinode will always be produced at
A
the closed end
B
the open end
C
the middle
D
all the parts of the pipe
correct option: b
Users' Answers & Comments25
A steel wire of length 0.50m is stretched between two fixed points and its fundamental frequency is 200Hz. The speed of the wave in the wire is
A
100ms-1
B
120ms-1
C
200ms-1
D
250ms-1
correct option: c
In strings, \(\lambda\) = 2L
V = F\(\lambda\)
= 200 x 2 x 0.5
= 200ms-1
Users' Answers & CommentsV = F\(\lambda\)
= 200 x 2 x 0.5
= 200ms-1
26
In a resonance tube experiment, if the fundamental frequency of the vibrating air column is 280Hz, the frequency of the third overtone is
A
70Hz
B
840Hz
C
1120Hz
D
1960Hz
27
An object 0 lies at a distance m in front of concave mirror of focal length f. If m < f, then the final image obtained will be
A
virtual and diminished
B
magnified and erect
C
real and inverted
D
diminished and erect
correct option: c
Users' Answers & Comments28
An object is placed in front of two plane mirrors inclined at an angle of 0o. If the total number of images formed is 7, Find the value of \(\theta\)
A
30o
B
45o
C
51o
D
90o
correct option: b
Number of image = \(\frac{360}{\theta}\) -1
7 = \(\frac{360}{\theta}\) -1
thus,\(\theta\) = 45o
Users' Answers & Comments7 = \(\frac{360}{\theta}\) -1
thus,\(\theta\) = 45o
29
The most suitable type of mirror used for the construction of the search light is the
A
concave mirror
B
convex mirror
C
spherical mirror
D
parabolic mirror
correct option: d
Users' Answers & Comments30
The displacement d produced in a glass block of thickness t and refractive index n when an object is viewed through it is
A
t – n
B
t (1 + 1/n)
C
t (1-1/n)
D
t (1/n - 1)
correct option: c
n = \(\frac {\text{real depth}}{\text {apparent depth}{}}\)
n = \(\frac {t}{t-d}\)
\(\frac{t - d}{1}\) = \(\frac{t}{n}\)
-d = \(\frac{t}{n}\) - t
d = - \(\frac{t}{n}\) + t
d = t - \(\frac{t}{n}\)
d =t (1 - \(\frac{1}{n}\))
Users' Answers & Commentsn = \(\frac {t}{t-d}\)
\(\frac{t - d}{1}\) = \(\frac{t}{n}\)
-d = \(\frac{t}{n}\) - t
d = - \(\frac{t}{n}\) + t
d = t - \(\frac{t}{n}\)
d =t (1 - \(\frac{1}{n}\))