Common Mistakes to Avoid in PN Cadet Physics Tests for 100% Success
PN Cadet Physics Tests (Part-3)
41. At what angle above the horizon must the sun be to create a rainbow?
A. 90 degrees
B. 60 degrees
C. 40 degrees
D. 65 degrees
Correct Answer: C. 40 degrees
42. The ozone layer is at a height of ______ kilometers from the surface of the Earth?
A. 10 to 20
B. 20 to 30
C. 30 to 40
D. 40 to 50
Correct Answer: B. 20 to 30
43. Sound cannot travel through:
A. Solid
B. Liquid
C. Gases
D. Vacuum
Correct Answer: D. Vacuum
44. The speed of sound in air at sea level is approximately ______?
A. 300 meter per second
B. 320 meter per second
C. 340 meters per second
D. 370 meter per second
Correct Answer: C. 340 meters per second
45. 1 angstrom is equal to ______?
A. 10⁻⁸ mm
B. 10⁻⁶ cm
C. 10⁻¹⁰ m
D. 10⁻¹⁴ m
Correct Answer: C. 10⁻¹⁰ m
46. One newton meter is same as ______?
A. One watt
B. One joule
C. Five joules
D. One joule second
Correct Answer: B. One joule
47. One Quintal is Equal to ______?
A. 70 kg
B. 80 kg
C. 90 kg
D. 100 kg
Correct Answer: D. 100 kg
48. The Scientist who told “Heat is a form of Energy” was ______?
A. Thomas Alva Edison
B. Newton
C. Joule
D. Kepler
Correct Answer: C. Joule
49. Fine organic or inorganic particles suspended in air is called ______?
A. Particulate pollutant
B. Gaseous pollutant
C. Aerosol
D. None of these
Correct Answer: C. Aerosol
50. The temperature at which water boils depends mainly on ______?
A. Air temperature
B. Relative humidity
C. Air pressure
D. Air density
E. The specific heat of air
Correct Answer: C. Air pressure
51. Melanoma (skin cancer) is associated with ______?
A. Ozone accumulation
B. Ozone depletion
C. Acid rain
D. Allergens
Correct Answer: B. Ozone depletion
52. The earth’s atmosphere is divided into layers based on the vertical profile of ______?
A. Air pressure
B. Air temperature
C. Air density
D. Wind speed
Correct Answer: B. Air temperature
53. A step-down chopper can be used in ______?
A. Electric traction
B. Electric vehicles
C. Machine tools
D. All of these
Correct Answer: D. All of these
54. The output current in PWM DC – DC converters is equal to ______?
A. Average value of the output inductor current
B. Product of an average inductor current and a function of duty ratio
C. Either A or B
D. None of these
Correct Answer: A. Average value of the output inductor current
55. The opposite of susceptibility is ______?
A. Immunity
B. Emission
C. Interference
D. Electromagnetic compatibility
Correct Answer: A. Immunity
56. Regulator sampling PWM is usually used in ______?
A. High power inverters
B. Rectifiers
C. Low power inverters
D. Only A and B
Correct Answer: D. Only A and B
57. A combination of synchronized leading edge and trailing edge modulation has also been used to control a ______?
A. Boost single – phase power factor converter
B. A buck dc – dc converter to reduce ripple in the intermediate dc bus capacitor
C. Both A and B
D. None of these
Correct Answer: C. Both A and B
58. If energy is taken from the AC side of the inverter and sent back into the DC side, then it is known as ______?
A. Motoring mode operation
B. Braking mode operation
C. Regenerative mode operation
D. None of these
Correct Answer: C. Regenerative mode operation
59. The ac output voltage waveform of VSI and AC output current waveform of CSI respectively is composed of ______?
A. High dv/dt, low di/dt
B. Low dv/dt, low di/dt
C. Low dv/dt, high di/dt
D. High dv/dt, high di/dt
Correct Answer: D. High dv/dt, high di/dt
60. An RC snubber network used in BJT ______?
A. Divert the collector current during turn – off
B. Improves the reverse bias safe operating area
C. Dissipates a fair amount of switching power
D. All of these
Correct Answer: D. All of these
