Physics (Railway) Part-I

Total Questions: 50

11. Sound travels at a speed of 333 ms-¹ in the air, thus, in 1 s, a distance of 333 m is travelled by: [RRB ALP & Technician Exam, 10.08.2018 Shift-I]

Correct Answer: (4) disturbance
Solution:A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The particles of medium are not carried along the waves; it is the disturbance which moves and forms the wave.

12. The tendency of undisturbed objects to stay at rest or to keep moving with the same velocity is called________. [RRB ALP & Technician Exam, 10.08.2018 Shift-I]

Correct Answer: (2) Inertia
Solution:Inertia is a property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force. It is a passive property and does not enable a body to do anything except oppose such active agents as forces and torques. It is described by Newton's First Law of Motion.

13. When a compressed slinky is released it converts potential energy into: [RRB ALP & Technician Exam, 10.08.2018 Shift-1)]

Correct Answer: (2) Kinetic energy
Solution:When slinky is compressed work is done against the spring force, and this work done is stored as potential energy. A compressed slinky or spring stores potential energy as long as it is compressed. So, when it is released, it converts potential energy into kinetic energy.

14. According to Ohm's law, if current (1) increases and potential difference (V) remains constant, then: [RRB ALP & Technician Exam, 10.08.2018 Shift-I]

Correct Answer: (4) resistance decreases
Solution:Ohm's law states that the electrical current (I) flowing in a circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, if the current is increased, the resistance will provided the voltage of the circuit does not change.

15. What does Coulomb's Law state? [RRB ALP & Technician Exam, 10.08.2018 Shift-III]

Correct Answer: (2) The magnitude of the force of attraction (or repulsion) between two point charges is directly proportional to the product of the quantity of the two charges and inversely proportional to the square of the distance between them.
Solution:According to Coulomb's Law, the magnitude of the force of attraction (or repulsion) between two point charges is:

➤  directly proportional to the magnitude of each charge.

➤ inversely proportional to square of the separation between their centers.

➤ directed along the separation vector connecting their centers,

16. Name the type of mirror used in the headlight of vehicles: [RRB ALP & Technician Exam, 10.08.2018 Shift-III]

Correct Answer: (4) Concave mirror
Solution:Concave mirrors are used in vehicle headlights to send out strong beams of light. Instead of reflecting an image, they are used to focus the light from the bulb. Rays of light from the bulb are reflected off the concave mirror, creating a strong beam that shines on the road. Concave mirrors are mirrors that curve inward. Used to focus light inward toward one focal point.

17. Which of the following is a Non-Luminous body? [RRB ALP & Technician Exam, 10.08.2018 Shift-III]

Correct Answer: (2) Moon
Solution:A luminous object is one that gives off light because of its own source of energy. Moon is a non-luminous object as it reflects back the sunlight during night.

18. The SI unit of electric charge is: [RRB ALP & Technician Exam, 10.08.2018 Shift-III]

Correct Answer: (4) coulomb
Solution:The coulomb is the International System of Units (SI) unit of electric charge. It is the charge transported by a constant current of one ampere in one second.

19. The second equation of motion gives the relation between: [RRB ALP & Technician Exam, 10.08.2018 Shift-III]

Correct Answer: (3) Position and time
Solution:The displacement of a moving object is directly proportional to both velocity and time. Thus, the second equation of motion gives relation between position and time. The second equation of motion is.

s = ut + 1/2 at²

where, s distance travelled by the object (position of the object)

u = Initical velocity

t = time

a = acceleration of the object

20. A ball of 0.1 kg is dropped from rest. When it falls through a distance of 2 m, the work done by the force of gravity is (g=9.8 m/s²): [RRB ALP & Technician Exam, 10.08.2018 Shift III]

Correct Answer: (3) 1.96 J
Solution:Work done by the gravity in this case will be positive as acceleration due to gravity is acting in the same direction of the ball.

Work done by the gravity

= mgh

=0.1 x 9.8 x 2

=0.2 x 9.8

= 1.96J