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 691:
Which of the following is not a consequence of hydrogen bubbles covering the copper plate of a primary cell?
Options:
A) formation of hydrogen bubbles on the electrode
B) increase in the resistance of the cell
C) local action
D) polarization
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The correct answer is C .
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Question 692:
In the diagram above, which of the following velocity-time graphs shows uniform acceleration of a body from rest?
Options:
A) C
B) D
C) B
D) A
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The correct answer is C .
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Question 693:
Rainbow formation is as a result of the combination of which of the following phenomena?
(i) Reflection
(ii) Dispersion
(iii) Total internal reflection
(iv) Refraction
Options:
A) (ii) and (iv) only
B) (i), (iii) and (iv) only
C) (ii), (iii) and (iv) only
D) (i), (ii) and (iv) only
Show Answer
The correct answer is C .
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Question 694: A machine has a velocity ratio of 4. if it requires 800 N to overcome a load of 1600 N,what is the efficiency of the machine?
Options:
A) 60%
B) 50%
C) 40%
D) 2%
Show Answer
The correct answer is B .
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Question 695:
A car of mass 800kg attains a speed of 25m/s in 20secs. The power developed in the engine is
Options:
A) 1.25 x 10W
B) 2.50x 10W
C) 1.25 x 10W
D) 2.50 x 10W
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The correct answer is A .
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Question 696:
In semi-conductor, the carriers of current at room temperature are
Options:
A) electrons only
B) electrons and holes
C) holes only
D) electron and ions
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The correct answer is B .
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Question 697: A thermometer with an arbitrary scale S, of equal division registers -30oS at the ice point and +90oS at the steam point. Calculate the Celsius temperature corresponding to 60oS
Options:
A) 25.0oC
B) 50.0oC
C) 66.7oC
D) 75.0oC
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The correct answer is D .
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Question 698: A machine whose efficiency is 60% has a velocity ratio of 5. If a force of 500N is applied to lift a load P, what is the magnitude of P?
Options:
A) 1500N
B) 500N
C) 4166N
D) 750N
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The correct answer is A .
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Question 699: A cell of internal resistance 1Ω supplies current to an external resistor of 3Ω. The efficiency of the cell is
Options:
A) 25%
B) 33%
C) 50%
D) 75%
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The correct answer is D .
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Question 700: What are the units of thermal conductivity?
Options:
A) kg.m.sec2
B) Joule sec-1m-1k-1
C) kg.m
D) Newton sec-1m2
E) m3
Show Answer
The correct answer is B .