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
41. The phenomena of raising the outer edge of the curved roads above the inner edge to provide necessary centripetal force to the vehicles to take a safe turn is called _____.
[A] banking of roads
[B] cornering of roads
[C] elevation of roads
[D] tempering of roads
Show Answer
Correct Answer: A [banking of roads]
Notes:
The phenomenon of raising outer edge of the curved road above the inner edge is to provide necessary centripetal force to the vehiclesto take a safer turn and the curved road is called Banking of Roads. If a car is on a level (unbanked) surface, the forces acting on the car are its weight, mg, pulling the car downward, and the normal force, N, due to the road, which pushes the car upward. Both of these forces act in the vertical direction and have no horizontal component. If there is no friction, there is no force that can supply the centripetal force required to make the car move in a circular path – there is no way that the car can turn.
42. When a wooden spoon is dipped in a cup of ice cream, its other end will__:
[A] become cold by the process of conduction
[B] become cold by the process of convection
[C] become cold by the process of radiation
[D] not become cold
Show Answer
Correct Answer: D [not become cold]
Notes:
A wooden spoon is dipped in a cup of ice cream but its other end will not become cold as wood is bad conductor of heat.
43. To hear a distinct echo, the time interval between the original sound and reflected sound must be atleast ______.
[A] 0.1 seconds
[B] 0.2 seconds
[C] 0.3 seconds
[D] 0.4 seconds
Show Answer
Correct Answer: A [0.1 seconds]
Notes:
Echo is defined as the reflection of sound, arriving at the listener some time after the direct sound. As the sensation of sound persists in brain for about 0.1 s, to hear a distinct echo the time interval between the original sound and the reflected one must be at least 0.1s.
44. Which contact force is responsible for changing the state of motion of an object?
[A] Magnetic force
[B] Frictional force
[C] Muscular force
[D] Electrostatic force
Show Answer
Correct Answer: B [Frictional force]
Notes:
The force responsible for changing the state of motion of objects is the force of friction. The frictional force always acts on all the moving objects and its direction is always opposite to the direction of motion. Since the force of friction arises due to contact between surfaces, it is also an example of a contact force.
45. The product of force and the time for which the force acts on a body is equal to the change in ________ of the body.
[A] acceleration
[B] torque
[C] momentum
[D] velocity
Show Answer
Correct Answer: C [momentum]
Notes:
A large amount of force acting on an object for a period of time is called impulse or impulsive force. Numerically, impulse is the product of force and time. Impulse of an object is equal to the change in momentum of the object. In other words, Impulse is a change of momentum produced, equivalent to the average value of the force multiplied by the time during which it acts.
46. Which of the following phenomena is involved in Kaleidoscope?
[A] Refraction
[B] Reflection
[C] Total Internal reflection
[D] Diffraction
Show Answer
Correct Answer: B [Reflection]
Notes:
A kaleidoscope is an optical instrument with two or more reflecting surfaces inclined to each other in an angle, so that one or more objects on one end of the mirrors are seen as a regular symmetrical pattern when viewed from the other end, due to repeated reflection. It operates on the principle of multiple reflection, where two or more reflectors are placed at an angle to one another.
47. Which among the following is most helpful in energy savings?
[A] Incandescent bulb
[B] Fluorescent tube light
[C] Compact fluorescent lamp
[D] LED bulb
Show Answer
Correct Answer: D [LED bulb]
Notes:
Light Emitting Diode (LED) is the most energyefficient and rapidly-developing lighting technology. LED bulbs last up to 10 times as long as compact fluorescents, and far longer than typical incandescent. LED light bulbs use only 2-17 watts of electricity (1/3rd to 1/30th of Incandescent or CFL).
48. Magnetic keepers are pieces of__:
[A] Nickel
[B] Cobalt
[C] Steel
[D] Soft iron
Show Answer
Correct Answer: D [Soft iron]
Notes:
Magnetic keepers are pieces of soft iron that are placed across the poles of a bar magnet or a horseshoe magnet. They help prevent the loss of magnetism. i.e. help retain the magnetic strength of the magnates placed together.
49. Name the process by which bubbles from liquid are formed?
[A] Effervescence
[B] Surface Tension
[C] Surface Energy
[D] Degasification
Show Answer
Correct Answer: A [Effervescence]
Notes:
Effervescence is the escape of gas from an aqueous solution and the foaming or fizzing that results from a release of the gas. It leads to the formation of gas bubbles in a liquid. For example, when opening a bottle of champagne, beer or carbonated beverages such as soft drinks, the visible bubbles are produced by the escape of the dissolved gas from solution.
50. The force of attraction between an electron revolving around the nucleus and the nucleus is a _________ force?
[A] Mechanical
[B] Electric
[C] Magnetic
[D] Gravitational
Show Answer
Correct Answer: B [Electric]
Notes:
Electrons revolve around the nucleus in circular orbits of all possible radii. The necessary centripetal force for circular motion of electrons around the nucleus is provided by electrostatic force of attraction between electrons and nucleus.
