UNN Physics 2009/2010 Past Questions

Practice each question, then open it to see the full details.

A body falls freely under gravity (g = 9.8m/s²) from a height of 10m on top of a platform 0.8m above the ground. Its velocity on reaching the platform is

A.78.48m/s
B.80m/s
C.78m/s
D.27.78m/s

Objective

Question 2

A hydrometer is an instrument used for measuring the

A.depth of water in a vessel
B.relative density of a liquid by method of flotation
C.relative density of a liquid by finding the apparent loss in weight
D.relative humidity of the atmosphere

Objective

Question 3

A bead travelling on a straight wire is brought to rest at 0.2m by friction. If the mass of the bead is 0.01kg and th coefficient of friction between the bead and the wire is 0.1, determine the work done by friction

A.2 x 10^-4 J
B.2 x 10³ J
C.2 x 10⁴ J
D.2 x 10² J

Objective

Question 4

A machine whose efficiency is 60% has a velocity ratio of 5. If a force of 500N is applied to lift a load of P(N), what is the magnitude of P?

A.750N
B.4166N
C.500N
D.1500N

Objective

Question 5

A mass of gas at 7°C and 70 cm of mercury has a volume of 1200cm³. Determine its volume at 27°C and a pressure of 75cm of mercury

A.1200cm³
B.1378cm³
C.4320cm³
D.4629cm³

Objective

Question 6

A motor tyre is inflated to a pressure of 2.0 x 10⁵ Nm^-2 when the temperature of air is 27°C. What will be the pressure at 87°C assuming the volume does not change?

A.2.6 x 10⁵Nm^-2
B.2.4 x 10⁵Nm^-2
C.2.2 x 10⁵Nm^-2
D.1.3 x 10⁵Nm^-2

Objective

Question 7

A beam of light is incident from air to water at an angle of 30°. Find the angle of refraction if the refractive index of water is 4/3.

A.15°
B.18°
C.22°
D.240°

Objective

Question 8

The wavelength of signal from a radio transmitter is 1500m and the frequency is 200KHz. What is the velocity of the propagation?

A.3 x 10⁸ms^-1
B.7 x 10³ms^-1
C.3 x 10⁴ms^-1
D.7ms^-1

Objective

Question 9

A boy on looking into a mirror discovers that his face appeared to have grown bigger. The boy must have been looking at a

A.convex mirror with his face at the focus
B.concave mirror with his face between the focus and the mirror
C.convex mirror with his face between the focus and the mirror
D.concave mirror with his face at the focus

Objective

Question 10

Find the frequencies of the first three harmonics of a piano string of length 1.5m, if the velocity of the string is 120m/s.

A.40Hz, 80Hz, 120Hz
B.180Hz, 360Hz, 540Hz
C.80Hz, 160Hz, 240Hz
D.360Hz, 180Hz, 90Hz

Objective

Question 11

The resistance of a piece of wire of length 20cm and cross-sectional area 8 x 10⁵ m² and resistivity 4 x 10^-7 ohm/m

A.1.0 ohm
B.10.0 ohm
C.400.0 ohm
D.1.0 x 10^-13 ohm

Objective

Question 12

An electric device is rated 2000W, 250V. The correct fuse rating of the device is

A.8A
B.9A
C.7A
D.6A

Objective

Question 13

Determine the inductive reactance when a 30.0mH inductor with negligible resistance is connected to a 1.3KHz oscillator

A.39.0 ohm
B.122.5 ohm
C.245.0 ohm
D.39 kohm

Objective

Question 14

The half-life of a radioactive element is 9days. Calculate the fraction that remains after 36 days.

A.1/32
B.1/16
C.1/4
D.15/32

Objective

Question 15

The graphite rods surrounding the uranium fuel rods in a nuclear reactor are used to

A.absorb the neutrons and hence halt the nuclear process
B.create the neutrons and hence slow down the nuclear process
C.slow down the neutrons and hence slow down the nuclear process
D.speed up the neutrons and hence speed up the nuclear process

Objective