1- Complete the following statements:
(5 marks)
(a) Polarization of light occurs by ………………… and by reflection.
(b) In a thermodynamic cyclic process, the change in internal energy of the system is ……………
(c) The electric power delivered in an electric iron of resistance 20  and takes a current of 5A is
……………………
(d) Interference of light waves occurs only if the waves are ………………
(e) The energy required to convert 1 g of ice to water at 0 oC is ……………… (Lf = 3.33 x 106 J/kg)
2- A 1.5 kg piece of iron initially at 600 °C is dropped into a bucket containing 20 kg of
water at 25 °C. What is the final temperature?
(3 marks)
c iron = 448 J/kg.oC
c water = 4186 J/kg.oC
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3- A 2 mol sample of an ideal gas initially at 300 K and 0.4 atm is compressed
isothermally to 1.2 atm. Find (a) the final volume of the gas, (b) the work done on the
gas, and (c) the energy transferred by heat.
(3 marks)
R = 8.314 J/K.mol
1atm = 1.013 x 105 Pa
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4- A 0.9 V potential difference is maintained across a 1.5 m length of tungsten wire that
has a cross-sectional area of 0.6 mm2. What is the current in the wire? (3 marks)
Resistivity of tungsten ρ = 5.6 x 10-8 Ω.m
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5- Young’s double-slit experiment is performed with 589 nm light and a distance of 2 m
between the slits and the screen. The tenth interference minimum is observed 7.26 mm
from the central maximum. Determine the spacing of the slits.
(3 marks)
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6- Coherent microwaves of wavelength 5 cm enter a long, narrow window in a building
otherwise essentially opaque to the microwaves. If the window is 36 cm wide, what is
the distance from the central maximum to the first-order minimum along a wall 6.5 m
from the window?
(3 marks)
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