UNN Physics 2008/2009 Past Questions

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

A body of mass 5kg initially at rest is acted upon by two mutually perpendicular forces 12N and 5N as shown in the figure below.

If the particle moves in the direction QA, calculate the magnitude of the acceleration

A.2.60 m/s²
B.0.26 m/s²
C.3.40 m/s²
D.1.40 m/s²
E.0.40 m/s²

A car of mass 1500kg goes round a circular curve of radius 50m at a speed of 40m/s. The magnitude of centripetal force on the car is

A.1.2 x 10² N
B.1.2 x 10³ N
C.4.8 x 10³ N
D.4.8 x 10⁴ N

The efficiency of a machine is always less than 100% because

A.load lifted is always greater than work input
B.load lifted is always greater than the applied effort
C.effort applied is always greater than mechanical advantage
D.velocity ratio is always greater than the mechanical advantage

Which of these statements is not true?
Thermostats are used to control the temperature of

A.pressure cookers
B.laundry irons
C.hot water storage tanks
D.aquaria for tropical fish

A given mass of an ideal gas occupies a volume V at a temperature T and under a pressure P. If the pressure is increased to 2P and the temperature reduced 1/2T, then the percentage change in volume of the gas is

A.25%
B.75%
C.300%
D.1%

The thermometric property of a constant volume thermometer is

A.change in pressure
B.change in length
C.differential expansion
D.change in volume

The combination of sound waves with different frequencies is known as

A.interference
B.diffraction
C.superposition
D.resonance

Which of the following characteristics of a wave used in the measurement of the depth of the sea?

A.refraction
B.reflection
C.diffraction
D.interference

Which of the following eye defects can be corrected using a cylindrical lens?

A.Astigmatism
B.Presbyopia
C.Chromatic aberration
D.Myopia

The resistance of a wire depends on

A.the length of the wire
B.the area of the wire
C.the temperature of the wire
D.all of the above

A dynamo primarily converts

A.mechanical energy into electrical energy
B.electrical energy into kinetic energy
C.potential energy into kinetic energy
D.kinetic energy into potential energy

If a current carrying coil is mounted on a metal frame, the back emf induced in the coil causes

A.inductance
B.eddy current
C.electromagnetism
D.dipole moment

Which of the following may be found in light nuclei?
I. beta particles
II. protons
III. neutrons
IV alpha particles

A.I and II only
B.I and III only
C.I and IV only
D.II and III only

The difference between X-rays and γ-rays is that

A.X-rays arise from energy changes and are due to electrons while γ-rays come from the nucleus
B.X-rays are electromagnetic radiations while γ-rays are not
C.X-rays have higher frequencies than γ-rays
D.X-rays are more penetrating than γ-rays

When an atom loses or gains a charge, it becomes

A.an electron
B.an ion
C.a neutron
D.a proton