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 231: In a semi conductor junction diode, as the depletion or barrier layer is forward-biased, the layer
Options:
A) widens
B) narrows
C) remains constant
D) widens then narrows
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The correct answer is C .
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Question 232: If a pump is capable of lifting 5000kg of water through a vertical height of 60m in 15 min, the power of the pump is
Options:
A) 2.2.5 x 10 5js-1
B) 2.5 x 104js-1
C) 3.3 x 103js-1
D) 3.3 x 102js-1
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The correct answer is C .
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Question 233: When a certain a.c supply is connected to a lamp, it lights with the same brightness as it does with a 12 V d.c battery. Then r.m.s value of the a.c supply is?
Options:
A) 12.0 V
B) 3.5 V
C) 17.0 V
D) 8.5
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The correct answer is A .
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Question 234: A jet engine develops a thrust of 270Ns when the velocity of the exhaust gases relative to the engine is 300ms-1. What is the mass of the material ejected per second?
Options:
A) 81.00kg
B) 9.00kg
C) 0.90kg
D) 0.09kg
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The correct answer is C .
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Question 235: A 90cm uniform lever has a load of 30N suspended at 15cm from one of its ends. If the fulcrum is at the center of gravity, the force that must be applied at its other end to keep it in horizontal equilibrium is
Options:
A) 15N
B) 20N
C) 30N
D) 60N
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The correct answer is B .
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Question 236: The iron core of an induction coil is made from bundles of wire so as to
Options:
A) minimize eddy-currents
B) generate eddy-current
C) prevent sparking at the contact breaker
D) get the greatest posible secondary voltage
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The correct answer is A .
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Question 237: The process of energy production in the sun is
Options:
A) nuclear fission
B) nuclear fussion
C) electron collision
D) radioactive decay
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The correct answer is B .
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Question 238:
A ray of light passes through the centre of curvature of a concave mirror and strikes the mirror. At what angle is the ray reflected?
Options:
A) 180
B) 90
C) 0
D) 60
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The correct answer is C .
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Question 239:
In the figure above if the atmospheric pressure is 760mm, the pressure of the chamber G is
Options:
A) 660mm
B) 690mm
C) 830mm
D) 860mm
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The correct answer is C .
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Question 240: The difference between X-rays and gamma rays is that
Options:
A) x-rays are more penetrating than gamma rays
B) x-rays are electromagnetic radiations while gamma rays are negatively charged radiation
C) x-rays have higher frequencies than gamma rays
D) x-rays arise from energy changes in the electronic structure of atoms while gamma rays come from the nucleus
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The correct answer is D .