Physics (Part-X) (Railway)

Total Questions: 51

41. What is the temperature at which the readings on the Celsius and Fahrenheit scales are equal? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) -273 degrees
(2) -40 degrees
(3) 100 degrees
(4) 0 degree

Correct Answer: (2) -40 degrees

Solution:Celsius is directly proportional to Fahrenheit. With the Increase in the temperature on the Celsius scale, its Fahrenheit temperature equivalent temperature will also rise.

• A point on both scales where the temperatures in degrees are equal - 40°.

42. Which statement correctly describes the difference between direct current (DC) and alternating current (AC)? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) High voltage DC is used in electronics while batteries give AC output.
(2) DC flows in one direction. while AC keeps changing direction at a fixed frequency.
(3) The frequency of DC is 50 Hz, while the frequency of AC is 100 Hz
(4) DC is used as domestic supply to homes, whereas AC is not used for domestic supply.

Correct Answer: (2) DC flows in one direction. while AC keeps changing direction at a fixed frequency.

Solution:In Direct Current (DC), the electric charge (current) only flows in one direction.

• Electric charge in Alternating Current (AC) changes direction periodically.

• The voltage in AC circuits also periodically reverses because the current changes direction.

43. What is the density of an object whose mass is 500 grams and volume is 200 cm³? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) 2.5 g/cm³
(2) 2.0 g/cm³
(3) 1.5 g/m³
(4) 0.4 g/cm³

Correct Answer: (1) 2.5 g/cm³

Solution:Density = Mass/Volume

= 500 gram/200 cm³

= 2.5 g/cm³

44. What is the principle of energy conservation in the context of work and energy? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) The total energy of an open system remains constant with time.
(2) Energy can neither be created nor destroyed, but can only be transferred or transformed.
(3) The efficiency of a machine can be more than 100%.
(4) The rate of change of energy is equal to the applied force.

Correct Answer: (2) Energy can neither be created nor destroyed, but can only be transferred or transformed.

Solution:Law of conservation of energy states that energy is neither created nor destroyed.

• The energy can only be converted from one form to another form.

• For example, electric heater converts electric energy into heat energy, electric bulb converts electrical energy into light energy, etc

45. Which of the following is an example of non-renewable energy source? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) Solar energy
(2) Hydroelectric energy
(3) Nuclear energy
(4) Wind energy

Correct Answer: (3) Nuclear energy

Solution:The resources that are limited and which may not exist in the future are known as non-renewable resources.

• There are four major types of non-renewable resources: oil, natural gas, coal, and nuclear energy.

46. Which of the following substances is the best conductor of heat? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) Steel
(2) Copper
(3) Plastic
(4) Glass

Correct Answer: (2) Copper

Solution:The materials which allow heat to pass through them easily are conductors of heat. For examples, aluminum, iron and copper.

• The best conductors of heat are silver and copper.

• Copper has the highest heat conductivity value, while steel has the lowest heat conductivity value.

• Poor conductors are known as insulators.

47. A car, a bus and a truck are traveling at the same speed. Which vehicle has more kinetic energy? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) Truck
(2) Bus
(3) The heaviest vehicle will have more kinetic energy.
(4) Car

Correct Answer: (3) The heaviest vehicle will have more kinetic energy.

Solution:Kinetic energy depends on mass and velocity (or speed):

KE = (1/2)/mv2 .

• At the same speed, the heavier vehicle will have more kinetic energy.

48. Which of the following is a unit of energy? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) Joule
(2) Tor
(3) Newton
(4) Pascal

Correct Answer: (1) Joule

Solution:Energy is the quantity required to perform work on or by an object.

• Energy is transferred to an object and work is done on the object or by the object.

• The SI unit of both the work and energy is Joule.

49. Which law of thermodynamics says that energy can neither be created nor destroyed, but can only be transferred or transformed? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) Second law of thermodynamics
(2) Third law of thermodynamics
(3) Fourth law of thermodynamics
(4) Zeroth law of thermodynamics

Correct Answer: (2) Third law of thermodynamics

Solution:The first law of thermodynamics states that the energy of the universe remains the same.

• The energy of an isolated system is constant.

• It is commonly stated as the law of conservation of energy i.e., energy can neither be created nor be destroyed.

50. Transformer is used in electric circuit? [RRC NWR Jaipur GDCE ALP Exam, 22.07.2023 (Shift-II)]

(1) To increase or decrease the voltage.
(2) To convert AC to DC.
(3) To increase or decrease power.
(4) To increase or decrease the frequency.0

Correct Answer: (1) To increase or decrease the voltage.

Solution:A transformer is commonly used to increase or decrease the supply voltage without a change in the frequency of AC between circuits.

• A transformer designed to increase the voltage from primary to secondary is called a step up transformer.

• A transformer designed to reduce the voltage from primary to secondary is called a step down transformer.

« Previous 1 2 3 456 Next »