Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
11. Which of the following waves is absorbed by the ozone layer present in the atmosphere?
[A] Gamma
[B] Visible
[C] Radio
[D] Ultra violet
Show Answer
Correct Answer: D [Ultra violet]
Notes:
UV light in large quantities has harmful effects on humans. But fortunately, most of it is absorbed in the ozone layer in the atmosphere at an altitude of about 40 – 50 km.
12. What is the effect of increase of temperature on the speed of sound?
[A] it increases
[B] it decreases
[C] it may or may not increase
[D] No effect
Show Answer
Correct Answer: A [it increases]
Notes:
In any medium as we increase the temperature the speed of sound increases. For example, the speed of sound in air is 331 m s–1 at 0 ºC and 344 m s–1 at 22 ºC.
13. Which of the following is correct about compressions in sound wave?
[A] compressions are regions of low pressure and low density
[B] compressions are regions of high pressure and low density
[C] compressions are regions of high pressure and high density
[D] compressions are regions of low pressure and high density
Show Answer
Correct Answer: C [compressions are regions of high pressure and high density]
Notes:
Compressions are the regions where particles are crowded together and represented by the upper portion of the curve. Compressions are regions where density as well as pressure is high.
14. What do we call the mode of transmission of heat by which heat travels from one part of a body to another by the actual motion of the heated particles of the body?
[A] Conduction
[B] Convection
[C] Radiation
[D] None of the above
Show Answer
Correct Answer: B [Convection]
Notes:
Convection is that mode of transmission of heat by which heat travels from one part of a body to another by the actual motion of the heated particles of the body.
15. What do we call the process taking place at constant temperature?
[A] Adiabatic
[B] Isothermal
[C] Isochoric
[D] isobaric
Show Answer
Correct Answer: B [Isothermal]
Notes:
A change in pressure and volume of a gas without any change in its temperature, is called an isothermal change and the process taking place at constant temperature is called as Isothermal process.
16. What is the temperature range used in the definition of a calorie?
[A] 12.5° C to 13.5° C
[B] 13.5° C to 14.5° C
[C] 14.5° C to 15.5° C
[D] 15.5° C to 16.5° C
Show Answer
Correct Answer: C [14.5° C to 15.5° C]
Notes:
One calorie is defined to be the amount of heat required to raise the temperature of 1g of water from 14.5 °C to 15.5 °C.
17. Which of the following is the commercial unit of electric power?
[A] Joule
[B] KWh
[C] Watt
[D] Ampere
Show Answer
Correct Answer: B [KWh ]
Notes:
The commercial unit of electric power or electric energy is s kilowatt hour (kW h) which is commonly known as ‘unit’.1 kWh= 3.6 x 106 Joule. The SI unit of electric power is watt (W).
18. Which of the following metals is mostly used for filaments of electric bulbs?
[A] Copper
[B] Silver
[C] Nickel
[D] Tungsten
Show Answer
Correct Answer: D [Tungsten ]
Notes:
Tungsten is mostly used to manufacture filaments of electric bulbs. Among all the metals, Tungsten has the highest melting point. Its symbol is W, its atomic number is 74, and its atomic weight is 183.85. It is used in many other high temperature application because of its high melting point.
19. Which of the following nuclear processes is the source of energy output in the interior of stars?
[A] Nuclear Fission
[B] Nuclear Fusion
[C] Both a and b
[D] None
Show Answer
Correct Answer: B [Nuclear Fusion]
Notes:
Thermonuclear fusion is the source of energy output in the interior of stars.
20. What is a p-n diode said to be in reverse-bias?
[A] positive terminal of the external battery is connected to the p-side
[B] positive terminal of the external battery is connected to the n-side
[C] negative terminal of the external battery is connected to the n-side
[D] None of the above
Show Answer
Correct Answer: B [positive terminal of the external battery is connected to the n-side]
Notes:
If the positive terminal of the external battery is connected to the n-side and the negative terminal of the external battery is connected to the p- side, then the p-n junction is said to be reverse biased.
