Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India.
21. What is the effect of rise of temperature on the time period of a simple pendulum?
[A] it increases
[B] it decreases
[C] it may or may not increase
[D] No relationship
Show Answer
Correct Answer: A [it increases]
Notes:
If the bob of simple pendulum is suspended by a wire then effective length of pendulum will increase with the rise of temperature due to which the time period will increase.
22. Which of the following represents the speed of a sound wave?
[A] wavelength x frequency
[B] 2 x wavelength x frequency
[C] wavelength/frequency
[D] (wavelength x frequency)/2
Show Answer
Correct Answer: A [wavelength x frequency]
Notes:
The speed of sound is defined as the distance which a point on a wave, such as a compression or a rarefaction, travels per unit time. It is represented by s = wavelength x frequency.
23. Which of the following is correct about the properties of Sound waves?
[A] Sound waves are longitudinal waves
[B] Sound waves are transverse waves
[C] Sound waves are both longitudinal and transverse
[D] None of the above
Show Answer
Correct Answer: A [Sound waves are longitudinal waves]
Notes:
Sound waves are longitudinal waves. In these waves the individual particles of the medium move in a direction parallel to the direction of propagation of the disturbance.
24. What do we call the energy transferred between two systems by virtue of temperature difference?
[A] Kinetic Energy
[B] Potential Energy
[C] Heat Energy
[D] Mechanical Energy
Show Answer
Correct Answer: C [Heat Energy]
Notes:
Heat is the form of energy transferred between two (or more) systems or a system and its surroundings by virtue of temperature difference.
25. Which of the following represents the Boiling process?
[A] Adiabatic change
[B] Isothermal change
[C] Isochoric process
[D] None
Show Answer
Correct Answer: B [Isothermal change]
Notes:
Boiling and Melting both are an example of Isothermal processes because temperature is constant.
26. What do we call a device by which a system is made to undergo a cyclic process resulting in conversion of heat to work?
[A] Heat engine
[B] Refrigerator
[C] No such device exists
[D] None of the above
Show Answer
Correct Answer: A [Heat engine]
Notes:
Heat engine is a device by which a system is made to undergo a cyclic process that results in conversion of heat to work.
27. Which of the following gives the power of a lens?
[A] equal to its focal length
[B] reciprocal of its focal length
[C] half of its focal length
[D] double the focal length
Show Answer
Correct Answer: B [reciprocal of its focal length]
Notes:
The power of a lens is defined as the reciprocal of its focal length.
28. Which is the direction of magnetic field inside a magnet?
[A] from south pole to north pole
[B] from north pole to south pole
[C] from north pole till centre of the magnet
[D] None of the above
Show Answer
Correct Answer: A [from south pole to north pole]
Notes:
Inside the magnet, the direction of field lines is from its south pole to its north pole.
29. Which of the following is the function of calorimeter?
[A] Measures the amount of calories in the body
[B] Measures the heat of chemical reactions and physical change
[C] Measures the density of an object
[D] None of the above
Show Answer
Correct Answer: B [Measures the heat of chemical reactions and physical change]
Notes:
A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal micro calorimeters, titration calorimeters and accelerated rate calorimeters are among the most common types.
30. Which of the following devices is best suited for measuring the temperature inside metallurgical furnaces?
[A] Pyrometer
[B] Thermistor
[C] Thermocouple
[D] Thermometer
Show Answer
Correct Answer: A [Pyrometer]
Notes:
Pyrometer is a device for measuring relatively high temperatures, such as are encountered in furnaces. Most pyrometers work by measuring radiation from the body whose temperature is to be measured.
