PHYSICS 2021 UTME PAST QUESTION
1. The law of conservation of energy is represented by
A. Lenz’s law
B. Ampere’s law
C. Coulomb’s law
D. Faraday’s law
In the figure above, the value of R at balance point is
A. 6.00
B. 10.30
C. 11.25
D. 5.00
3. The area under a force –distance curve is
A. Work
B. Impulse
C. Pressure
D. Momentum
4. A charge of 30 Uc a force of 60N at a certain point. The electric fields intensity due to the charge is
A. 5×104
4
NC
-1
B. 2×10
4
NC
-1
C. 5×10
6
NC
-1
D. 2×10
6
NC
-1
5. Dams are usually thicker at the bottom because
A. The water pressure exerted are strongest close to the ground
B. The water pressure is weakest close to the ground
C. Water has a greater pressure close to the ground
D. Water has a lesser pressure close to the ground
6. Which of the following pairs gives vector quantities
A. Momentum and power
B. Energy and impulse
C. Mass and mechanical advantage
D. Weight and movement
7. An equipment which is 1,500W and resistance 375 would draw a current of
A. 77.5A
B. 4A
C. 0.1
D. 0.2
8. Which of the following gives white colours when combined
A. Red + magenta + green
B. Blue + red + cyan
C. Red + green + blue
D. Red + cyan + blue
9. Which of these losses occur in a transformer?(i) hysteresis loss (ii) Eddy current loss (iii) stray load loss (iv)mechanical loss
A. I and II only
B. I and III only
C. I, II, and IV only
D. I, II, and III
10. What is the correct formula for the efficiency of a device?
A. Input /Output
B. Output/Losses
C. Losses/(output + losses
D. 1- losses/ Output + losses
11. The inductance of a turning circuit of Am radio is 4mH. Find the capacitance of the circuit required for reception at 1,200kHz
A. 2.1 PF
B. 4.4 PF
C. 21.2PF
D. 27.6PF
12. Calculate the time required to electroplate a substance of area 300 cm
2
with a layer of copper 0.6mm thick, if a steady current of 2A is maintained. Assuming the density of copper is 0.008kg/cm
2
and mass of copper liberated per coulomb is 3.3×10
-7
kg/C.
A. 6.67hr
B. 10.25hr
C. 66.67hr
D. 0.67hr
13. Which of the following velocity – time graph most suitable represent a solid ice puck pushed forward on a smooth horizontal surface?
A.
B.
C.
D.
14. Which of these electrical instrument or machines does not rely on the magnetic effect of current for its working?
A. Carbon microphone
B. Telephone receiver
C. Moving – coil galvanometer
D. Dynamo
15. A50W heating coil is used for 2 minutes to heat a spherical metal ball of mass 0.5Jkg and specific heat capacity of 1,000Jkg
-1
k
-1
. The temperature rises is?
A. 25
o
C
B. 24
o
C
C. 12
o
C
D. 60
o
C
16. A closed jar contains air at 1 atmosphere and 27o. when the jar is heated to 127o what will be the pressure increase? A. 11/3 atm
A. 1
1/3
atm
B. 3
1/3
atm
C. 1/3 atm
D. ½ atm
17. A wire A is half the length and half the diameter of a wire B of similar material. What is the ratio of the resistance of B to that of A?
A. 8:1
B. 1:2
C. 2:1
D. 1:4
18. In any machine, (i) the velocity ratio is usually greater than the mechanical advantage (ii) the efficiency equals ratio of mechanical advantages to the velocity ratio (iii) the velocity ratio is independent of friction. Which of the statement above is/are correct?
A. i only
B. i and ii only
C. ii and iii only
D. i, ii and iii
19. The accommodation of the eyes is
A. Produced by movement of the retinal
B. Due to change of size of the pupils
C. Produced by the action of the ciliary muscles
D. As a result of unbalanced diet
20. A ball of mass 500g,he released from a cliff 20m above ground, rebounce to a heights of 5m. if the ball is in contact with ground for 0.1s, calculate the force acting on the ball on impact with ground
A. 50N
B. 100N
C. 150N
D. 200N
21. A vibrating string has a tension of when plunked in the middle the lenth of the string is unaltered and the tension is increased by 120N , then the new frequency becomes?
A. 1,600Hz
B. 25Hz
C. 200Hz
D. 400Hz
22. A parallel arrangement of 3hms and 6hms resistor is placed in series with an 8hms resistor. If a potential difference of 30V is connected across the whole circuit, the current in the 3hms resistor is
A. 15A
B. 10A
C. 3A
D. 2A
23. A 60W and a 120W domestic lamp are use on the 240V mains. Which of the following statement is correct?
A. The filament of the 120W lamp has a higher resistance than that of the 60W lamb
B. The total current through the mains is 1 ampere.
C. The potential difference across each lamp is 120W
D. The filament of the 60W has a higher resistance than that of the 120W lamp
24. A converging lens has a focal length of 20cm. the lens form a real inverted image of the same size as the object distance from the lens is?
A. 40cm
B. 30cm
C. 20cm
D. 10cm
25. X-ray are very useful in all of these except
A. In the treatment of cancer and detection of broken bones
B. In the investigation of structure of crystal
C. In detecting defect in metals
D. In the determination of the estimate of estimates of specimen’s age
26. 1F caesium has a work function of 1.9ev, calculate its threshold wavelength (assume 1ev=1.6×10
-19
J, h=6.6×10p
-34
Js, C =3×10
8
m/s)
A. 3.5×10
-34
Js
B. 6.5×10
-7
m
C. 7.7×10
-7
m
D. 8.6×10
-7
m
27. The specific latent heat of stream is 2,300J/g and specific heat capacity of water is 4.2J/gk. When 2g of stream at 100
o
C condense to water at 40o C, the heat given up is
A. 5.,104J
B. 4,936J
C. 4,636J
D. 4,684J
28. When a gas is compressed at constant temperature, the gas molecules
A. Gain kinetic energy
B. Increase slightly in size
C. Move at the same speed so that the pressure is unchanged
D. Make more impacts per second on the walls of the container
The note from a plunked guitar string will have a low pitch if the strings is
A. Thin and short
B. Thick and long
C. Thick and slack
D. Thick and short
30. The half – life of an element is 24 hours. What fraction of the atoms has disintegrated in 72 hours?
A. 7/8
B. 1/8
C. 1/8
D. ¼
31. Two equal masses placed 2m apart, have a gravitational attraction of 6.7×10
-9
N. compute the value of the masses [assume, G=6.7×10
-11
Nm
2
/kg
2
]
A. 20Kg
B. 30Kg
C. 40Kg C
D. 50Kg
32. The potential at a point distance 0.03m from a small charge q is – 1.0×10
5
V. What is the magnitude of q? [Assume1/(4 pi!)=9×10
9
Nm
2
C
-2
]
A. -3.3×10
-7
N
B. -3.3×10
-7
C
C. 1.1×10
-7
C
D. -1.1×10
-7
N
33. The wave theory of light CANNOT be used to explained photoelectricity because
A. Light wave do not carry energy
B. There is threshold wave length for electron emission
C. Wavelength of lightwave is too short
D. Particles cannot be emmited by wave
34. Which of the following statement is true?
A. A boy walking on a tight rope
B. A balloon on a smooth horizontal table
C. A ball resting on an inverted hemispherical bowl
D. A ball in the middle of hemispherical bowl
35. Petrol produce a cooling effect cause it has
A. Low conductivity
B. High conductivity
C. High latent heat of vaporization
D. Low latent heat of vaporization
36. Which of the following observation cannot be explained using rectilinear equation
A. Diffraction pattern of light
B. Formation of annular eclipse
C. Production of real image
D. Production of image by a pinhole camera
37. Neutron are used to induced artificial radioactivity because they
A. Have no charge
B. Have no mass
C. Are more energetic
D. Are very ionizing
38. Which of these method cannot be used to reduced the surface tension of a liquid
A. Addition of detergent or soap
B. Addition of oil
C. Addition of alcohol
D. Reducing temperature of the liquid
39.
40.
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