2017 - JAMB Physics Past Questions and Answers - page 4
31
A constant force of %n acts for a % seconds on a mass of 5kg initially at rest. Calculate the final momentum
A
125kgms−1
B
25kgms−1
C
15kgms−1
D
0kgms−1
correct option: b
Impulse = momentum
Impulse = Force (f) × time (t)
Momentum = mass (m) × velocity (v)
∴ Ft = Final momentum - initial momentum
FT = mv - mu
Since it is initially at rest u = 0
∴ 5 × 5 = mv − m(0)
25 = mv
∴ Final momentum = 25kgms\(^{-1}\)
Users' Answers & CommentsImpulse = Force (f) × time (t)
Momentum = mass (m) × velocity (v)
∴ Ft = Final momentum - initial momentum
FT = mv - mu
Since it is initially at rest u = 0
∴ 5 × 5 = mv − m(0)
25 = mv
∴ Final momentum = 25kgms\(^{-1}\)
32
I. Refraction II. Interference III. Diffraction Which of the above properties are common to all waves?
A
II and III only
B
I, II and III
C
I and II only
D
I and III only
correct option: b
Refraction, Interference and diffraction are all properties of waves
Users' Answers & Comments33
I. Refraction II. Interference III. Diffraction Which of the above properties are common to all waves?
A
II and III only
B
I, II and III
C
I and II only
D
I and III only
correct option: b
Refraction, Interference and diffraction are all properties of waves
Users' Answers & Comments34
Which of the following is correct about an electric cell?
A
Primary cell produces a large current for a long time
B
Secondary cell has a very high internal resistance
C
Primary cell has a very low internal resistance
D
Secondary cell has a very low internal resistance
correct option: d
About electric cell
Primary cells are used up gradually often the cells are use and it can't be recharged
Secondary cells or accumulated can be recharged and used for a long period of time and their main advantage is that they have low internal resistance
Users' Answers & CommentsPrimary cells are used up gradually often the cells are use and it can't be recharged
Secondary cells or accumulated can be recharged and used for a long period of time and their main advantage is that they have low internal resistance
35
Which of the following is a semiconductor
A
copper
B
silicon
C
plastic
D
Iron
correct option: b
Semi-conductor have an elecctric conductivity intermediate in value between that of a pure metal and a good insulator. Silicon is an example
Users' Answers & Comments36
Which of the following surfaces will absorbs radiant heat energy heat?
A
white
B
red
C
black
D
blue
correct option: c
A black solution is a better radiator of heat and allow a better absorber of heat.
Users' Answers & Comments37
It is known that a neutron exists in a light atomic nucleus
Which of the following also exists in the nucleus?
Which of the following also exists in the nucleus?
A
An electron
B
A β - particle
C
β - particle
D
proton
38
The instrument to measure the relative density of light is
A
thermometer
B
hydrometer
C
spring balance
D
beaker
correct option: b
Thermometer is used to measure temperature
Hydrometer is used to measure relative density of liquid.
Spring balance is used to measure the weight of an object
Beaker is used to measure or take volume of a liquid
Users' Answers & CommentsHydrometer is used to measure relative density of liquid.
Spring balance is used to measure the weight of an object
Beaker is used to measure or take volume of a liquid
39
What is the speed of a body vibrating at 50 cyclic per second
A
100 πrads\(_{−1}\)
B
200 πrads\(_{−1}\)
C
50 πrads\(_{−1}\)
D
400 πrads\(_{−1}\)
correct option: a
1 cycle = 3600 = 2π rad
∴ 50 cycle = 2 π rad × 50 = 100 πrad
∴ = angular speed = 50 cycles per seconds = 100 π rads\(_{−1}\)
Users' Answers & Comments∴ 50 cycle = 2 π rad × 50 = 100 πrad
∴ = angular speed = 50 cycles per seconds = 100 π rads\(_{−1}\)
40
The action of blotting paper on ink is due to
A
diffusion
B
osmosis
C
capillarity
D
surface tension
correct option: c
Capillarity is the tendency of a liquid to rise or fall in a narrow tube and it explains why a blotting paper absorbs ink
Users' Answers & Comments