Physics is the science that studies the nature and properties of matter and energy. It covers topics like motion, heat, light, sound, electricity, magnetism, and the structure of atoms.
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Question 161:
A semiconductor is formed by?
Options:
A) co-ordinate bonds
B) electrovalent bonds
C) a substance free of bonds
D) covalent bonds
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The correct answer is D .
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Question 162:
A bridge made of steel is 600m long. What is the daily variation in its length if the night-time and daytime temperatures are 10oC and 35oC respectively. The linear expansivity of steel is 0.000012C-1
Options:
A) 0.18cm
B) 1.80cm
C) 18.00cm
D) 1800cm
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The correct answer is C .
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Question 163:
0.5kg of water at 10ºC is completely converted to ice at 0ºC by extracting (88000) of heat from it. If the specific heat capacity of water is 4200jkg Cº. Calculate the specific latent heat of fusion of ice.
Options:
A) 9.0kjkg
B) 84.0kjkg
C) 134.0kjkg
D) 168.0kjkg
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The correct answer is C .
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Question 164: Equal masses of copper and rubber are raised to the same temperature. After sometimes, the copper was observed to be at a lower temperature because
Options:
A) the specific heat capacity of copper is lower than that of rubber
B) copper expands more than rubber
C) the specific heat capacity of rubber is lower than that of copper
D) rubber expands more than copper
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The correct answer is A .
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Question 165:
Which of these is observed when air is pumped out of a discharge tube without lowering its pressure
Options:
A) the conductivity of the air increases
B) the conductivity of the air decreases
C) conduction does not occur
D) spark are produced
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The correct answer is C .
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Question 166:
The part of the human eye that does similar work as the diaphragm of a camera lens is the
Options:
A) Ciliary muscles
B) Pupil
C) Iris
D) Retina
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The correct answer is C .
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Question 167: Heat is supplied to a test tube containing 100g of ice at its melting point. The ice melts completely in 1 min.What is the power rating of the source of heat? [Latent heat of fusion of ice = 336Jg-1]
Options:
A) 336W
B) 450W
C) 560W
D) 600W
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The correct answer is C .
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Question 168:
The inside portion of part of a hollow metal sphere of diameter 20cm is polished. The portion will therefore form a?
Options:
A) concave mirror of focal length 5cm
B) concave mirror of focal length 10cm
C) convex mirror of focal length 5cm
D) convex mirror of focal length 10cm
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The correct answer is C .
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Question 169:
Calculate the gravitation force of attraction between two planets of 1024kg and 1027kg separated by a distance of 1020meters.
Options:
A) 6.67N
B) 6.56N
C) 7.5N
D) 8.6N
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The correct answer is A .
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Question 170:

In the figure above, XY is of length 1m, The value of R at balance point Z is
Options:
A) 3.0Ω
B) 13.3Ω
C) 15.0Ω
D) 30.0Ω
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The correct answer is D .