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Physics
UTME / JAMB 2009
Structure of the Nucleus
Solution
If the decay constant of a radioactive substance is 0.231s-\(^1\), the half-life is?
A
3.00 s
B
0.12 s
C
0.33 s
D
1.50 s
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
Half-life, T (1)/2 = (0.693)/∆ = (0.693)/ 0.231 = 3.0sec
Source: WAEC / JAMB / NECO Classroom Archive (Record #14265)
Physics
UTME / JAMB 2009
Structure of the Nucleus
Solution
A piece of radioactive material contains 10\(^{20}\) atoms.
If the half life of the material is 20 seconds, the number of disintegration in the first second is?
A
3.47 x 1018
B
6.93 x 10 20
C
3.47 x 1020
D
6.93 x 1018
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
The number of disintegration,∆N in time interval At, is given by
- ∆N = N∆t
Where N is the number of atoms present at the time t
But ^ = (0.693)/T
= 0.693 \div 20
= 0.0347
∴ ∆N = 0.0347 \(\times\) 10\(^20\)
= 3.47 \(\times\) 10\(^18\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #14266)
Physics
NECO SSCE 2009
Structure of the Nucleus
Solution
Determine the value of x from the nuclear reaction below,
\(^{222}_{86}Rn\) → \(^{x}_{88}Ra\) + 2β + energy
A
220
B
222
C
224
D
226
E
228
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
The equation above is Beta-decay:
where \beta is an electron → \(^{0} _{-1}e\)
2\beta in the equation = \(^{0} _{-1}e\) + \(^{0} _{-1}e\) → \(^{0} _{-2}e\)
\(^{222}_{86}Rn\) → \(^{x}_{88}Ra\) + \(^{0} _{-2}e\) + energy
where \(^{x}_{88}Ra\) + \(^{0} _{-2}e\) → \(^{222}_{86}Rn\)
: x = 222 for element Radon [ \(^{222}_{88}Ra\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #43045)
Physics
UTME / JAMB 2009
Structure of the Nucleus
Solution
The process of energy production in the sun is?
A
nuclear fission
B
nuclear fusion
C
electron collision
D
radioactive decay
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
The process of energy production in the sun is generally by nuclear fusion of hydrogen nuclei, the reaction of which takes place at a tremendous high temperature.
Source: WAEC / JAMB / NECO Classroom Archive (Record #61067)
Physics
UTME / JAMB 2009
Reflection of Light
Solution
I. Moon.
II. Sun.
III.street light.
IV. stars.
Which of these are natural sources of light?
A
II, III, and IV only
B
I, II and III only
C
III and IV only
D
II and IV only
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
The sun and stars are self luminous object.
Source: WAEC / JAMB / NECO Classroom Archive (Record #14204)
Physics
UTME / JAMB 2009
Reflection of Light
Solution
An object is placed 5 cm from the pole of a concave mirror. if the focal length of the mirror is 10 cm. what is the image distance?
A
10 cm in front of the mirror.
B
5 cm in front of the mirror
C
10 cm behind the mirror
D
5 cm behind the mirror
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
u = 5 cm , f = 10 cm, v = ?
(1)/v + (1)/u = (1)/f
(1)/v + (1)/5 = (1)/10
= (1)/v = (1)/10 - (1)/5
= (1 - 2)/10 = (1)/10
∴ v = - 10 cm
∴ The image is 10 cm behind the mirror
Source: WAEC / JAMB / NECO Classroom Archive (Record #14210)
Physics
UTME / JAMB 2009
Refraction of Light
Solution
If the refractive index of crown glass is 1.51, its critical angle is?
A
48.6°
B
22.5°
C
41.5°
D
45.0°
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
Sin c = (1)/n
= (1)/1.51 = 0.6622
∴ c = sin-\(^1\) 0.6622 = 41.47
Source: WAEC / JAMB / NECO Classroom Archive (Record #14215)
Physics
UTME / JAMB 2009
Sound Wave
Solution
Metal cables are used as telephone wires because?
A
they are cheap
B
they are sourced locally
C
the speed of sound in them is very low
D
the speed of sound in them is very high
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
The speed of sound is highest in solid.
Metals (solids) like copper, steel rod, etc
Source: WAEC / JAMB / NECO Classroom Archive (Record #14200)
Physics
UTME / JAMB 2009
Sound Wave
Solution
Musical instruments playing the same note can be distinguished from one another owing to the differences in their?
A
quality
B
pitch
C
intensity
D
loudness
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
The quality of a note is a characteristic that distinguishes it from note of the same frequency played by another musical instrument.
Source: WAEC / JAMB / NECO Classroom Archive (Record #14201)
Physics
NECO SSCE 2009
Sound Wave
Solution
An observer heard the sound of thunder 5.8s after the lightning flash was seen. How far was he from the source? [Speed of sound in air = 330ms-1]
A
957m
B
1914m
C
3828m
D
8700m
E
17400m
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
VELOCITY=DISTANCE/TIME
Distance = 330\times5.8 Distance = 1914m
Source: WAEC / JAMB / NECO Classroom Archive (Record #43042)
Physics
UTME / JAMB 2009
Application of Lens
Solution
The ability of the human eye to focus object on the retina is referred to as the power of?
A
interference
B
diffraction
C
accomodation
D
superposition
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
Accommodation is the adjustment of the optics of the eye to keep an object in focus on the retina as its distance from the eye varies.
Source: WAEC / JAMB / NECO Classroom Archive (Record #14244)
Physics
UTME / JAMB 2009
Heat Energy & Temperature
Solution
I. Diameter of a small ball bearing.
II. Thickness of a pieces of paper.
III. Diameter of a measuring cylinder.
IV. Length of a piece of wire.
Which of the above can be measured using a micrometer screw gauge?
A
I, II and IV only .
B
I and II only
C
II and III only
D
III and IV only
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
Of all the instruments used in measuring length,the micrometer screw gauge has the highest reading accuracy (0.01 mm), and is therefore used in measuring very small length such as diameter of a small ball bearing, and thickness of a piece of paper.
Source: Myschool Past Questions Archive (Record #14138)
Physics
UTME / JAMB 2009
Waves and Optics
Solution
Calculate the position of an object placed in front of a convex mirror having focal length of 12 cm such that an image is formed 6 cm away from the mirror
A
4. 0 cm
B
3. 0 cm
C
12.0 cm
D
9.0 cm
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
f = -12 cm, v = - 6 cm
(1)/v + (1)/u =(1)/f
(1)/-6 + (1)/u = (1)/-12
(1)/u = (1)/-12 + (1)/6 = (1 + 2)/12 = (1)/12
∴ u = 12 cm
Source: Myschool Past Questions Archive (Record #14213)
Physics
UTME / JAMB 2009
Waves and Optics
Solution
When light passes through two media x and y of refraction indices 1.51 and 1.33 respectively, the speed of light in
A
x is same as in y
B
x and y is same as in vacuum
C
x is higher than in y
D
y is higher than in x
medium Difficulty
Verified Correct Answer: Option D
Physical Principles & Numerical Solution
Since 1.51, the refractive index of X is greater than 1.33, the refractive index of y, the speed of light in y is higher than that in X
Source: Myschool Past Questions Archive (Record #14237)
Physics
UTME / JAMB 2009
Heat Energy & Temperature
Solution
Which of the following is a secondary colour
A
blue
B
orange
C
red
D
green
medium Difficulty
Verified Correct Answer: Option B
Physical Principles & Numerical Solution
Primary colours are red, blue and green
∴ orange is a secondary colour
Source: Myschool Past Questions Archive (Record #14246)