51. Light year is a unit of
A. time
B. distance
C. light
D. intensity of light
✅ The correct answer is option B.
Physics MCQs
52. Intensity of sound has
A. an object existence
B. a subject existence
C. no existence
D. both subjective and objective existence
✅ The correct answer is option A.
53. Suitable impurities are added to a semiconductor depending on its use. This is done in order to
A. increase its life
B. enable it to withstand higher voltages
C. increase its electrical conductivity
D. increase its electrical resistivity
✅ The correct answer is option C.
54. One should not connect a number of electrical appliances to the same power socket because
A. this can damage the appliances due to overloading
B. this can damage the domestic wiring due to overloading
C. this can damage the electrical meter
D. the appliance will not get full voltage
✅ The correct answer is option B.
55. Intensity of sound at a point is ____ its distance from the source.
A. directly proportional to
B. inversely proportional to
C. directly proportional to square of
D. inversely proportional to square of
✅ The correct answer is option D.
56. Stars appears to move from east to west because
A. all stars move from east to west
B. the earth rotates from west to east
C. the earth rotates from east to west
D. the background of the stars moves from west to east
✅ The correct answer is option B.
57. RADAR is used for
A. locating submerged submarines
B. receiving a signals in a radio receiver
C. locating geostationary satellites
D. detecting and locating the position of objects such as aeroplanes
✅ The correct answer is option D.
58. Supersonic plane fly with the speed
A. less than the speed of sound
B. of sound
C. greater than the speed of sound
D. of light
✅ The correct answer is option C.
59. Lux is the SI unit of
A. intensity of illumination
B. luminous efficiency
C. luminous flux
D. luminous intensity
✅ The correct answer is option A.
The SI unit of intensity of illumination (illuminance) is the lux. An illuminance of 1.0 lux is produced by 1.0 lumen of light shining on an area of 1.0 m^2.
The SI unit of intensity of illumination (illuminance) is the lux. An illuminance of 1.0 lux is produced by 1.0 lumen of light shining on an area of 1.0 m^2.
60. One thousand microns is equal to
A. 10-3m
B. 10-6m
C. 10-9m
D. 10-12m
✅ The correct answer is option A.