Physics Questions And Answers

29. What element’s three isotopes have different names?  
A. Helium
B. Oxygen
C. Carbon
D. Hydrogen

30. The noise level of 100 decibel would correspond to :
a. Just audible sound 
b. ordinary conversation 
c. sound from a noisy street 
d. noise from a machine shop

31. newton is used to measure
a. Speed
b. Volume
c. Force
d. Area

32. A passenger in a moving train tosses a coin upward which falls behind him. It implies that the motion of the train is____?
a.  accelerated
b.  uniform
c.  retarded
d.  along the circular tracks

33. What is the principle by which a cooling system (Radiator) in a motor car works ? 
a. Conduction only 
b. convection 
c. radiation only 
d. both conduction and radiation 

34. The wavelength of X-rays is of the order of  
A.  1 cm
B.  1 m
C.  10 micron
D.  1 Angstrom

35. Decibel is the unit of: 
a. Speed of light >
b. intensity of sound 
c. intensity of heat 
d. none of these 

36. A lens, immersed in a liquid becomes in visible when 
a. the focal length of the lens is zero 
b. the focal length of the lens is infinite 
c. the refractive index of the lens is less than the refractive index of the liquid 
d. the refractive index of the lens is equal to the refractive index of the liquid

37. Which one of the following does TV remote control unit use to operate a TV set ?
a. light waves 
b. sound waves 
c. micro waves 
d. radio waves

38. What is newton third law of motion ?
a. Every body maintains its initial state rest or motion unless no external force is applied.
b. The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.
c. To every action there is equal and opposite reaction.
d. None of above.

39.Which of the following is the best conductor of the heat: 
a. mercurty 
b. silver 
c. leather 
d.benzene 

40. Definition of force comes from Newton’s ____________?
a. first law of motion
b. second law of motion
c. third law of motion
d. law of gravitation

41. Which one of the following is a good conductor of electricity?  
A.  Shellac
B.  Ebonite
C.  Glass
D.  Human body

42. One astronomical unit is the average distance between 
a. Earth and the Sun 
b. Earth and the moon 
c. Jupiter and the Sun
d. Pluto and the Sun 





                                                Answers

29. Answer : D. Hydrogen

30. Answer:
noise from a machine shop 

31. Answer: Option C

32. Ans. A
Accelerated
Acceleration is the rate of change of velocity of an object. An object's acceleration is the net result of any and all forces acting on the object.

33. Answer: convection 

34. Answer : D.  1 Angstrom

35. Answer: intensity of sound 

36. Answer: the refractive index of the lens is equal to the refractive index of the liquid

37. Answer: >radio waves

38. Answer: Option C
Explanation:
Newton First Law of Motion : Every body maintains its initial state rest or motion unless no external force is applied.
Newton Second Law of Motion : The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.
 View Answer

39. Answer: >silver

40. Ans. B
Second law of motion
Newton’s Second law: The vector sum of the external forces F on an object is equal to the mass m of that object multiplied by the acceleration vector a of the object: F = ma.

41. Answer : D.  Human body

42. Answer: Earth and the Sun 

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