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# How to solve some UTME physics past questions

Question 1

Which of the following consists entirely vector quantities? {UTME 2001}
A. Work, pressure and moment                 B. Velocity, magnetic flux and reaction.
C. Displacement, impulse and power.      D. Tension, magnetic flux and mass.

Solution

Vector quantities has both magnitude and direction

Option A – pressure and work are scalar quantities

Option B – they are all vector quantities

Option C- power is a scalar quantity

Option D – mass is a scalar quantity

B is the correct option

Question 2

A plane sound wave of frequency 85.5Hz and velocity 342ms-1 is reflected from a vertical wall. At what distance
from the wall does the wave have an antinode?{UTME 2001}
A. 0. 1m    B 1m     C. 2m      D. 3m

Solution

V =fℷ

ℷ = V/f = 342/85.5 = 4 m

distance to have an antinode = ℷ/4 = 4/4 = 1m

B is the correct option

Question 3

A string is fastened tightly between two walls 24cm apart. The wavelength of the second overtone is{UTME 2001}
A. 12cm         B. 24cm     C. 8cm      D. 16cm

Solution

third harmonic is the second overtone

second overtone = ℷ/2 + ℷ/2 +ℷ/2 = 3ℷ/2

3ℷ/2 = 24

ℷ = 16 cm

D is the correct option

Question 4

Find the frequencies of the first three harmonics of a piano string of length 1.5m, if the velocity of the waves on the
string is 120ms-1.{UTME 2001}
A. 180Hz, 360Hz, 540Hz.    B. 360Hz, 180Hz, 90Hz.
C. 40Hz, 80Hz, 120Hz.         D. 80Hz, 160Hz, 240Hz.

Solution

first harmonic = F0 = v/2l = 120/2*1.5 = 120/3 = 40Hz

second harmonic = 2f0 = 2*40 = 80Hz

third harmonic = 3f0 = 3*40 = 120Hz

C is the correct option

Question 5

A gas with initial volume 2 x 10-6m3 is allowed to expand to six times its initial volume at constant pressure of
2 x 105Nm-2. The work done is{UTME 2001}
A. 4.0J    B. 12.0J     C. 2.0J     D. 1.2J

Solution

workdone = pdv

dv =V2 – V1 = (6*2 x 10-6) – 2 x 10-6

dv = 12 x 10-6 – 2 x 10-6  = 10 x 10-6

workdone = 2 x 10^5 * 10 x 10-6 = 20 x 10^-1 = 2.0J

Question 6

The process of energy production in the sun is{UTME 2001}
A. radioactive decay   B. electron collision.
C. Nuclear fission.      D. Nuclear fusion

Solution

D is the correct option

Question 7

A student is at a height 4m above the ground during a thunderstorm. Given that the potential difference between
the thunderstorm and the ground is 107V, the electric field created by the storm is{UTME 2001}
A. 2.0 x 106NC-1.       B. 4.0 x 107NC-1.
C. 1.0 x 107NC-1.        D. 2.5 x 106NC-1

Solution

E = V/d = 10^7 / 4 = 2.5 x 10^6

D is the correct option

Question 8

An object is weighed at different locations on the earth. What will be the right observation?{UTME 2010}
A. Both the mass and weight vary   B. The weight is constant while the mass varies
C. The mass is constant while the weight varies   D. Both the mass and weight are constant.

Solution

The mass of an object doesnt change but weight changes because the force of gravity varies from place to place on the surface of earth.There are two reasons behind this variation:
The shape of earth and the rotation of the earth.

C is the correct option

Question 9

In a hydraulic press, the pump piston exerts a pressure of 100 Pa on the liquid. What force is exerted in the second piston of cross-sectional area 3m2?{UTME 2010}
A. 200 N    B. 100 N     C. 150 N     D. 300 N

Solution

Pressure = Force /Area

100 = force/3

force exerted = 300 N

Question 10

If the angle between two vectors P and Q is 0 degree, the vectors are said to
A. be perpendicular B. be parallel C. interest at angle 60o. D. intersect at angle 45o. (UTME 2004)

Solution

The angle between two parallel lines is zero, therefore, B is the correct option

Question 11

What happens to the rays in a parallel beam of light?
A. They diverge as they travel. B. They meet at infinity. C. They intersect D. They converge as they travel. (UTME 2004)

Solution

Parallel beam of light meet at infinity

B is the correct option

Question 12

The process whereby a liquid turns spontaneously into vapour is called
A. boiling  B. evaporation C. sublimation  D. relegation. (UTME 2005)

Solution

Solid to gas is sublimation

liquid to vapour at all temperature is evaporation

liquid to vapour at a fixed temperature is boiling

Since the word spontaneous is used in the question which means occur without having been planned, therefore, evaporation is the best answer.

B is the correct option

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