Railway Science (Physics-Miscellaneous)

Total Questions: 50

41. Which of the following statements is/are true? [RRB Group D 11/10/2018 (Morning)]

A. Rigidity: According to the type of matter, shape differs, depending upon location of particles. Eg, solids have definite shape while liquids acquire the shape of their container and gases, as such, don't have any shape.
B. Compressibility: It is the property of matter to allow a decrease in volume under high pressure and gases show this property.

Correct Answer: (b) A and B are both true
Solution:

Rigidity: Rigidity is the property of matter to resist the change in the shape of matter. Modulus of Rigidity = π‘†β„Žπ‘’π‘Žπ‘Ÿπ‘–π‘›π‘” π‘ π‘‘π‘Ÿπ‘’π‘ π‘ /π‘†β„Žπ‘’π‘Žπ‘Ÿπ‘–π‘›π‘” π‘ π‘‘π‘Ÿπ‘Žπ‘–π‘› , Fluidity: Fluidity is the property of matter by virtue of which matter flows.

42. What does the odometer of an automobile measure ? [RRB Group D 11/10/2018 (Afternoon)]

Correct Answer: (a) distance
Solution:

Instruments and their uses: Ammeter- Measures electric current in ampere. Barometer - Measures atmospheric pressure. Radiometer - Measures intensity or force radiation. Theodolite- Measures horizontal and vertical angles.

43. ____is used to measure the strength and velocity of wind. [RRB Group D 12/10/2018 (Morning)]

Correct Answer: (d) anemometer
Solution:

Other instruments and their uses: Speedometer: It is a scale that measures and represents the instantaneous speed of a vehicle. Lactometer: It is a small glass apparatus that is used to examine the purity of the milk. Thermometer: an instrument for measuring the temperature of a system.

44. Barometer is related to Pressure, in the same way as Seismograph is related to________. [RRB Group D 16/10/2018 (Evening)]

Correct Answer: (b) Earthquake
Solution:

A barometer is an instrument used to measure atmospheric pressure. A seismograph is an instrument used to detect and record earthquakes.

45. Which of the following resistors is known as a heat sensitive resistor ? [RRB Group D 26/10/2018 (Afternoon)]

Correct Answer: (a) thermistor
Solution:

A thermistor is a heat sensitive device whose resistivity changes very rapidly with change of temperature. A transistor is a type of semiconductor device that can be used to conduct and insulate electric current or voltage. A capacitor is a two-terminal electrical device that can store energy in the form of an electric charge.

46. Motion of a boy, sitting on a swing, is __________ . [RRB Group D 31/10/2018 (Afternoon)]

Correct Answer: (a) periodic
Solution:

The motion which repeats itself in equal intervals of time is known as periodic motion. Examples of periodic motions -The motion of a pendulum, the vibration of a guitar string, the rotation of the Earth about its axis, the revolving of the Earth around the Sun, and the revolving of the Sun around the center of the Galaxy, etc.

47. Negative acceleration is in the opposite direction of: [RRB ALP Tier - I (09/08/2018) Morning]

Correct Answer: (a) velocity
Solution:

Acceleration: The rate of change of velocity. It can have positive or negative values. Acceleration (a) = πΆβ„Žπ‘Žπ‘›π‘”π‘’ 𝑖𝑛 π‘£π‘’π‘™π‘œπ‘π‘–π‘‘π‘¦ (βˆ†π‘£)/π‘‘π‘–π‘šπ‘’(𝑑) , Unit - (m/sΒ²).

48. The first equation of motion gives the relation between: [RRB ALP Tier - I (10/08/2018) Afternoon]

Correct Answer: (c) velocity and time
Solution:

First Equation of Motion: v = u + at, Second Equation of Motion: s = u t + 1/2 atΒ², Third Equation of Motion: vΒ² = uΒ² + 2as. {Initial velocity (u), final velocity (v) and acceleration (a). Distance traveled - (s)}.

49. The second equation of motion gives the relation between: [RRB ALP Tier - I (10/08/2018) Evening]

Correct Answer: (b) Position and time
Solution:

Second Equation of Motion: s = ut + 1/2 atΒ² where s = distance traveled by the object, u = initial velocity, t = time and a = acceleration of the object.

50. Which of the following is a velocity-time graph for uniform motion of a car? Velocity (π‘šπ‘ β»ΒΉ) , Time (s) [RRB ALP Tier - I (10/08/2018) Evening]

Correct Answer: (b)
Solution:

Time graph of an object moving with uniform velocity is a straight line and parallel to the x-axis when velocity is taken along the y-axis and time is taken along the x-axis. Uniform motion - Velocity of the body is
constant with time. Example - velocity (v) = constant. Option (a) shows that, a non uniform motion (unequal distance covered by object in equal interval of time). Option (c) - If an object is moving with non uniform variation in velocity with time, the velocity time graph is a zigzag type. Option (d) - The nature of the graph clearly shows that velocity of the
object is changing by equal amounts in equal intervals of time.