Physics (Railway) Part-I

Total Questions: 50

41. What does the kinetic energy (KE) of a moving body depend upon? [RRB ALP & Technielan Exam, 14.08.2018 Shift-III]

Correct Answer: (4) Mass and velocity
Solution:The amount of kinetic energy in a moving object depends directly on its mass and velocity. An object with greater mass or greater velocity has more kinetic energy. If mass doubles, kinetic energy doubles as well, but if velocity doubles, kinetic energy increases by a factor of four. That's because velocity is squared in the equation.

42. If an object is placed at the centre of curvature of a concave mirror, then the image formed will be: [RRB ALP & Technician Exam, 14.08.2018 Shift-III]

Correct Answer: (2) real and of the same size
Solution:When the object is placed at the centre of curvature in case of concave mirror, the Image formed in this case is at the centre of curvature, of same size as the object, real and inverted.

43. What will be the resistance of a wire across which, when 2V potential difference is applied, 1A current flows through the wire? [RRB ALP & Technician Exam, 14.08.2018 Shift-III]

Correct Answer: (2) 2 Ohms
Solution:Given that the voltage (V) across the wire is 2V and current (I) flowing through if is 1A. Using Ohm's law.

R = V/I

R = 2/1

R = 2 Ohms.

44. The energy stored in a dry cell is in the form of: [RRB ALP & Technician Exam, 17.08.2018 Shift-I]

Correct Answer: (4) Chemical energy
Solution:A dry cell has chemical energy stored in it. The cell constitutes one or more electrochemical cells that translate the available chemical energy into electrical energy. The electrolyte inside the cell in form of paste minimizes the need for moisture and allows for portability.

45. One Watt = ? [RRB ALP & Technician Exam, 17.08.2018 Shift-I]

Correct Answer: (4) 1 Joule/sec
Solution:One watt is defined as the energy consumption rate of one joule per second. 1W = IJ/Is. It is the unit of power (symbol: W). The watt unit is named after James Watt, the inventor of the steam engine. One watt is also defined as the current flow of one ampere with voltage of one volt.

46. What will be the force of attraction between two bodies weighing 20kg and 50kg, respectively, with a distance of 2 metre between them? [RRB ALP & Technician Exam, 17.08.2018 Shift-I]

Correct Answer: (2) 166.75 x 10⁻¹⁰ N
Solution:If two bodies of masses, m, and m, are separated by a distance r, the force of gravitation (F) acting on the two bodies is given by:

F = Gm₁m₂/R² , where G is the

universal gravitational constant;

G = 6.67 * 10-¹¹ Nm²kg⁻²

So,

F = (6.67 * 10-¹¹ * 20 * 50 / 2²

= (6.67 * 10-¹¹ * 1000) / 4

= 166.75 * 10- 10-¹⁰  N

47. The tendency of undisturbed objects to stay at rest or to keep moving with the same velocity is called: [RRB ALP & Technician Exam, 17.08.2018 Shift-I]

Correct Answer: (4) 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 in Newton's First Law of Motion.

48. Which of the following glows with special colour depending on the nature of gas in the fluorescent tube? [RRB ALP & Technician Exam, 17.08.2018 Shift-I]

Correct Answer: (1) Plasma
Solution:The fluorescent tubes and neon sign bulbs consist of plasma, made up of super energetic and super excited particles in the form of ionized gases. The plasma glows with a special colour depending on the nature of the gas, when electric energy flows through it.

49. What enables an electric current to flow in a circuit? [RRB ALP & Technician Exam, 17.08.2018 Shilt-I]

Correct Answer: (4) The motion of electrons
Solution:Electric current is flow of electrons in a conductor. The flowing electrons carries the negative charge. Since the positive charge is fixed, it is the negative charge that flows. The conventional electric current is in the direction of the flow of positive charge.

50. Sound is a: [RRB ALP & Technician Exam, 17.08.2018 Shift-III]

Correct Answer: (2) Mechanical wave
Solution:A mechanical wave is a wave that is not capable of transmitting its energy through a vacuum. Mechanical waves require a medium in order to transport their energy from one location to another. A sound wave is an example of a mechanical wave.