2015 - JAMB Physics Past Questions and Answers - page 7
61
Volatile liquids usually
A
Have high boiling points
B
have low boiling points
C
have high densities
D
have high melting points
correct option: b
Volatile liquids (i.e. Ammonia or Freon) are usually have low boiling point
Users' Answers & Comments62
When a man moves toward a plane mirror at a speed of 6m/s, the distance the man and his image increased at a speed of?
A
2 m/s
B
4 m/s
C
12 m/s
D
14 m/s
correct option: c
d = y, s = 6 m/s (The Man & Plane Mirror)
d – δy, s = (5 – ;6) m/s (The Man and Image)
d2 ÷ s1 = d2 ÷ s2, y ÷ 6 = 2y ÷ s + 6
Y (s + 6) = 2y × 6
s + 6 = 12
So = 12 – 6 = 6
Since S + 6 = 0
Then, S = 6 (substitute the value of S i.e S = 6)
Into S + 6 = 0
∴So = S + 6 = 6 + 6 = 12 m/s
∴ S = 12 m/s
Users' Answers & Commentsd – δy, s = (5 – ;6) m/s (The Man and Image)
d2 ÷ s1 = d2 ÷ s2, y ÷ 6 = 2y ÷ s + 6
Y (s + 6) = 2y × 6
s + 6 = 12
So = 12 – 6 = 6
Since S + 6 = 0
Then, S = 6 (substitute the value of S i.e S = 6)
Into S + 6 = 0
∴So = S + 6 = 6 + 6 = 12 m/s
∴ S = 12 m/s
63
Which of the following instrument is most accurately for comparing electromotive force (e.m.f) of two cells?
A
Voltmeter
B
Meter rule
C
Galvanometer
D
Potentiometer
correct option: d
Voltmeter: an instrument for measuring electric potential in volts
Galvanometer: it is a device used to indicate direction of a small electric current
Potentiometer: is a device for measuring or comparing e.m.fs of cells
Meter rule: measuring a distance at different points
Users' Answers & CommentsGalvanometer: it is a device used to indicate direction of a small electric current
Potentiometer: is a device for measuring or comparing e.m.fs of cells
Meter rule: measuring a distance at different points
64
In an inelastic collision
I. Energy is conversed
II. Energy is decreased
III. Energy is increased
IV. Linear momentum conversed
I. Energy is conversed
II. Energy is decreased
III. Energy is increased
IV. Linear momentum conversed
A
I only
B
II and IV only
C
II only
D
III only
correct option: b
In an inelastic collision, linear momentum is conserved and energy is decreased
Momentum and kinetic energy are conserved in elastic collision
Users' Answers & CommentsMomentum and kinetic energy are conserved in elastic collision
65
In which of the following device in the expansion of solid is a disadvantages?
I. Simple pendulum
II. Fire alarms
III. Thermostat
IV. Bimetallic thermometer
I. Simple pendulum
II. Fire alarms
III. Thermostat
IV. Bimetallic thermometer
A
III only
B
II & III only
C
I only
D
II, III & IV only
correct option: c
Simple pendulum does not depend on thermal expansion
Five alarms, Thermostat and Bimetallic thermometer are application of thermal expansion of solid
Users' Answers & CommentsFive alarms, Thermostat and Bimetallic thermometer are application of thermal expansion of solid
66
The normal temperature of human body is record at what ranges?
A
27°C to 43°C
B
30°C to 40°
C
98.4°C only
D
Between 35°C to 37°C
correct option: d
The range of temperature is between 35°C and 43°C but for normal temperature of human body is between the range of 35°C to 37°C respectively
Users' Answers & Comments67
The property of a body to remain at rest or to continue to move in a straight line is known as
A
force
B
Impulse
C
Energy
D
Inertia
correct option: d
Inertia: the property of a body that resists any change to its uniform motion, equivalent to its mass
Users' Answers & Comments68
Momentum and Kinetic energy are conserved in
A
Inelastic collision
B
Elastic collision
C
Explosion
D
Spacecraft
correct option: b
Momentum and kinetic energy are conversed in elastic collision
Users' Answers & Comments69
An alternating current with a frequency of 100HZ has a period of
A
0.03sec
B
0.01sec
C
0.04sec
D
0.15sec
correct option: b
F = 100HZ, period, T = 1/f = 1/100
= 0.01 sec
The period (T) = 0.01sec
Users' Answers & Comments= 0.01 sec
The period (T) = 0.01sec
70
If the volume of a gas is recoded as 76cm3 at a temperature of 27°C with a pressure of 800mmHg. What will be the volume of the gas at S.T.P?
A
36.2cm3
B
25.7cm3
C
72.8cm3
D
24.3cm3
correct option: c
General formular of Gas laws
(P1V1) ÷ T1= (P2V2) ÷ T2
P1 = 800mmHg, V, = 76cm3, Tr = 273 + 27 = 300k
P2 = 760mmHg, V2 = ? T2= 273 + 0 = 273 + 6 = 277k
(800 × 76) ÷ 300 = (760 × V2) ÷ 273
V2 = (300 × 76 × 273) ÷ (300 × 760) = 72.8 cm3
The volume of gas as S.T.P = 72.8 cm3
Users' Answers & Comments(P1V1) ÷ T1= (P2V2) ÷ T2
P1 = 800mmHg, V, = 76cm3, Tr = 273 + 27 = 300k
P2 = 760mmHg, V2 = ? T2= 273 + 0 = 273 + 6 = 277k
(800 × 76) ÷ 300 = (760 × V2) ÷ 273
V2 = (300 × 76 × 273) ÷ (300 × 760) = 72.8 cm3
The volume of gas as S.T.P = 72.8 cm3