1
Choose the correct answer for the following :
(10 marks)
(1)
A traveling wave that causes the elements of the medium to move perpendicular to the
direction of propagation is called:
A linear wave.
(2)
B
B sin  =mλ/d
D sin  = d/mλ
tan=n2/n1
compressible medium
C vacuum
D space
C T = 0
D P=0
The measuring unit of the thermal conductivity of a material is:
W/m2.oC
B
C J/Kg. oC
D .m
How much current does a 60 W light bulb draw when connected to its proper voltage, 120V?
A
(7)
B
B W =0
A W/m.oC
(6)
C
In an isovolumetric process, there is :
A Q=0
(5)
D longitudinal wave.
Sound waves are longitudinal and travel through :
A incompressible medium
(4)
C transverse wave.
Polarization occurs by reflection if the Brewster angle  achieves the condition:
A tan=n1/n2
(3)
sinusoidal wave.
1A
B
0.7 A
C 0.5 A
D
0.2 A
When unpolarized light with intensity Io passes through a linear polarizer at an angle of 45o,
its intensity I is given by :
A I = Io
(8)
I = 2Io
C
I = Io/2
D I = Io cos 45
The terminal voltage of a battery is given as:
A V= Ir -
(9)
B
V=  + Ir
B
C V=  - Ir
D V= I -  r
The energy required to melt 1 g of ice (Lf= 3.33 x 105 J/kg) at 0oC is :
A
3300 J
B
3.33 J
C
33.3 J
D 333 J
(10) Total internal reflection occurs when light travels from a medium of index of refraction n 1 to
another of index of refraction n2 , where:
A n1=n2
B
n1  n2
C
n1  n2
D n1 =1
2
Using Kirchhoff’s rules, find the currents in the electric circuit shown.
(5 marks)
3
An ideal gas initially at 300 K undergoes an isobaric expansion at 2.5 x 103 Pa. If the volume
increases from 1 m3 to 3 m3 and 12.5 kJ is transferred to the gas by heat, what are (a) the change in
its internal energy and (b) its final temperature?
(5 marks)
4 A resistor is constructed of a carbon rod that has a uniform cross-sectional area of 5 mm2. When
a potential difference of 15 V is applied across the ends of the rod, the rod carries a current of 4 x 10-3
A. Find (a) the resistance of the rod and (b) the rod’s length.
(the resistivity of carbon is  = 3.5x10-5 .m)
(5 marks)
5 A sinusoidal wave is described by: y = (0.25 m) sin(0.3x – 40t) , where x and y are in meters
and t is in seconds. Determine for this wave: (a) the wavelength (b) the wave speed.
(5 marks)
6 White light is spread out into its spectral components by a diffraction grating. If the grating has
2000 grooves per centimeter, at what angle does red light of wavelength 640 nm appear in first order?
(5 marks)
Show that the difference between decibel levels 1 and 2 of a sound is related to the ratio of the
distances r1 and r2 from the sound source by:
(5 marks)
7
With Best Wishes ,,,
Dr. Ahmed Ismail