Prasar Bharati Online Exam: Quiz!
Questions and Answers
- 1.
A is thrice as good as a workman as B and therefore is able to finish a job in 60 days less than B. Working together, they can do it in:
- A.
20 days
- B.
22 ½ days
- C.
30 days
- D.
25 days
Correct Answer
B. 22 ½ daysExplanation
A is three times as good as B, which means that A can complete a job three times faster than B. This implies that the ratio of their work rates is 3:1. If B takes x days to complete the job, then A takes x/3 days. It is given that A can finish the job in 60 days less than B, so we have the equation x - (x/3) = 60. Solving this equation, we find that x = 90. Therefore, B takes 90 days to complete the job, and working together, their combined work rate is 4 units per day. Hence, they can complete the job in 90/4 = 22 ½ days.Rate this question:
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- 2.
An alone can do a piece of work in 6 days and B alone in 8 days. A and B undertook to do it for Rs. 3200. With the help of C, they completed the work in 3 days. How much is to be paid to C?
- A.
325 Rs
- B.
Rs. 400
- C.
Rs. 800
- D.
600 Rs
Correct Answer
B. Rs. 400Explanation
A can do 1/6th of the work in a day and B can do 1/8th of the work in a day. Together, A and B can do 1/6 + 1/8 = 7/24th of the work in a day. In 3 days, they completed 3 * 7/24 = 7/8th of the work. The remaining 1/8th of the work was completed by C. Since A, B, and C were paid a total of Rs. 3200, C's share would be 1/8 * 3200 = Rs. 400.Rate this question:
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- 3.
A can do a piece of work in 4 hours; B and C together can do it in 3 hours, while A and C together can do it in 2 hours. How long will B alone take to do it?
- A.
8 hours
- B.
10 hours
- C.
12 hours
- D.
24 hours
Correct Answer
C. 12 hoursExplanation
Based on the given information, we can deduce that A's work rate is faster than B's and C's individually. When A and B work together, they complete 1/4 of the work in an hour. When A and C work together, they complete 1/2 of the work in an hour. From this, we can infer that B and C together can complete 1/3 of the work in an hour. Since A's work rate is faster than B's and C's individually, B's work rate must be slower than C's. Therefore, it will take B longer to complete the work on his own. The correct answer is 12 hours.Rate this question:
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- 4.
A can-do certain work at the same time which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in:
- A.
15 days
- B.
20 days
- C.
25 days
- D.
30 days
Correct Answer
C. 25 daysExplanation
If A and B together can do the work in 10 days, it means that in one day, they can complete 1/10th of the work. If C alone can do the work in 50 days, it means that in one day, C can complete 1/50th of the work. Therefore, in one day, A, B, and C together can complete (1/10 + 1/50) = 6/50th of the work. This means that B alone can complete (6/50 - 1/50) = 5/50th of the work in one day. Simplifying this fraction, we get B can complete 1/10th of the work in one day. Therefore, B alone can complete the work in 10 days.Rate this question:
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- 5.
A machine P can print one lakh books in 8 hours, machine Q can print the same number of books in 10 hours while machine R can print them in 12 hours. All the machines are started at 9 A.M. while machine P is closed at 11 A.M. and the remaining two machines complete work. Approximately at what time will the work (to print one lakh books) be finished?
- A.
12 : 30 P.M
- B.
1:00 P.M.
- C.
11: 30 A.M
- D.
2: 00 P.M.
Correct Answer
B. 1:00 P.M.Explanation
Machine P can print 1 lakh books in 8 hours, which means it can print 12,500 books per hour. Machine Q can also print 12,500 books per hour, and machine R can print 8,333 books per hour.
Machine P is closed at 11 A.M., which means it has worked for 2 hours and printed 25,000 books. The remaining two machines need to print 75,000 books in total.
Machine Q and R together can print 20,833 books per hour (12,500 + 8,333). Therefore, they will take approximately 3.6 hours (75,000 / 20,833) to print the remaining books.
Adding this time to 11 A.M., we get 2:36 P.M. However, since we are looking for an approximate time, we can round it to 1:00 P.M. as the work will be finished around that time.Rate this question:
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- 6.
When a ray of light enters glass from water, it bends:
- A.
Towards the normal due to decrease in the speed of light
- B.
Towards the normal due to increase in the speed of light
- C.
Away from the normal due to increase in the speed of light
- D.
Away from the normal due to decrease in the speed of light
Correct Answer
A. Towards the normal due to decrease in the speed of lightExplanation
When a ray of light enters glass from water, it bends towards the normal due to a decrease in the speed of light. This phenomenon is known as refraction. Refraction occurs because light travels at different speeds in different mediums. In this case, as light enters glass from water, it enters a medium where its speed decreases. This causes the light ray to bend towards the normal, which is an imaginary line perpendicular to the surface of the glass.Rate this question:
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- 7.
The velocity of light in water is:
- A.
1.08
- B.
1.33
- C.
1.66
- D.
1.09
Correct Answer
B. 1.33Explanation
The velocity of light in water is 1.33. This value is determined by the refractive index of water, which is a measure of how much the speed of light is reduced when it passes through a medium. In the case of water, the refractive index is approximately 1.33, meaning that light travels at a speed that is 1.33 times slower in water compared to its speed in a vacuum. This phenomenon is responsible for the bending of light when it passes from one medium to another, such as when a beam of light enters water and appears to change direction.Rate this question:
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- 8.
A convex lens magnifying glass is of:
- A.
Short focal length
- B.
Long focal length
- C.
Very long focal length
- D.
All the above
Correct Answer
A. Short focal lengthExplanation
A convex lens magnifying glass has a short focal length because it is designed to converge light rays and create a magnified image. A shorter focal length means that the lens can bring the image closer to the lens, resulting in a larger magnification.Rate this question:
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- 9.
The objective lens of a telescope forms:
- A.
Real image
- B.
Virtual image
- C.
Indistinct image
- D.
None of the above
Correct Answer
A. Real imageExplanation
The objective lens of a telescope forms a real image. This is because the objective lens collects and converges the light rays coming from distant objects, creating an inverted and magnified image that can be projected onto a screen or observed directly. A real image is formed when the light rays actually converge at a point, allowing it to be captured or observed.Rate this question:
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- 10.
Astigmatism is corrected by using:
- A.
Convex lens
- B.
Concave lens
- C.
Cylindrical lens
- D.
Plane lens
Correct Answer
D. Plane lensExplanation
Astigmatism is a refractive error that results in blurred vision at all distances. It occurs when the cornea or lens of the eye has an irregular shape, causing light to focus on multiple points rather than a single point on the retina. To correct astigmatism, a lens is used to compensate for the irregular shape of the cornea or lens. A plane lens, also known as a plano lens, has no curvature and does not alter the direction of light. Therefore, it is not effective in correcting astigmatism. The correct answer is likely a mistake or the question is incomplete.Rate this question:
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- 11.
Eye piece of telescope forms a:
- A.
Real image
- B.
Virtual image
- C.
Both the above
- D.
None of the above
Correct Answer
B. Virtual imageExplanation
The eyepiece of a telescope forms a virtual image. This is because the eyepiece is responsible for magnifying the image formed by the objective lens, which is a real image. The eyepiece uses a combination of lenses to bend the light rays and create an enlarged and magnified virtual image that can be viewed by the observer. This virtual image appears to be located at a distance behind the eyepiece, allowing the observer to see a magnified and focused view of distant objects through the telescope.Rate this question:
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- 12.
In India who is the chairman of the Planning Commission?
- A.
President
- B.
Prime Minister
- C.
Speaker
- D.
None of these
Correct Answer
B. Prime MinisterExplanation
The correct answer is Prime Minister. In India, the chairman of the Planning Commission is the Prime Minister. The Planning Commission is a government body responsible for formulating and implementing economic and social development plans in the country. As the head of the government, the Prime Minister plays a crucial role in setting the agenda and priorities for the country's development. Therefore, it is the Prime Minister who holds the position of the chairman of the Planning Commission.Rate this question:
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- 13.
How long can a Presidential ordinance remain in force?
- A.
1 year
- B.
6 months
- C.
2 months
- D.
None of these
Correct Answer
B. 6 monthsExplanation
A Presidential ordinance in India can remain in force for a maximum period of 6 months. The President has the power to issue ordinances when Parliament is not in session and immediate action is required. However, an ordinance needs to be approved by both houses of Parliament within 6 weeks of reassembly. If not approved, it ceases to be in force. Therefore, the correct answer is 6 months.Rate this question:
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- 14.
First Lok Sabha Speaker was:
- A.
G.V. Mavlankar
- B.
Meera Kumari
- C.
Ravi Singh
- D.
Hukam Singh
Correct Answer
A. G.V. MavlankarExplanation
G.V. Mavlankar was the first Lok Sabha Speaker. He served as the Speaker from 1952 to 1956. Mavlankar played a crucial role in establishing the parliamentary traditions and procedures in India. He was known for his impartiality and ability to maintain decorum in the House. Mavlankar's tenure as the Speaker set a strong foundation for the functioning of the Lok Sabha, making him the correct answer for the question.Rate this question:
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- 15.
Maximum time between two Session of Parliament is:
- A.
Six months
- B.
1 year
- C.
1 month
- D.
None of these
Correct Answer
A. Six monthsExplanation
The maximum time between two sessions of Parliament is six months. This means that there cannot be a gap of more than six months between the end of one session and the beginning of the next session. This ensures that there is regularity and continuity in the functioning of the Parliament. It allows for timely discussions, debates, and decision-making on important matters of governance and legislation.Rate this question:
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- 16.
Study the following bar-graph and answer the questions given below. Number of Bike A and B type sold over the years in thousand. What is the ratio between the total number of bikes of A in the years 2004, 2006, and 2007 together and the total number of bikes of B in years 2002, 2004, and 2005?
- A.
5:6
- B.
1:2
- C.
2:1
- D.
3:4
Correct Answer
B. 1:2Explanation
The ratio between the total number of bikes of type A in the years 2004, 2006, and 2007 together and the total number of bikes of type B in years 2002, 2004, and 2005 is 1:2.Rate this question:
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- 17.
Study the following bar-graph and answer the questions given below. The Number of Bike A and B type sold over the years in thousand. The number of bikes of B type in the year 2007 is what percent of the total number of bikes of B type in all the years together? (Round off to two digits after decimal).
- A.
15
- B.
7.5
- C.
30
- D.
20.25
Correct Answer
B. 7.5Explanation
The number of bikes of B type in the year 2007 is 7.5% of the total number of bikes of B type in all the years together. This can be calculated by dividing the number of bikes of B type in 2007 (15) by the total number of bikes of B type in all the years (200). Then, multiplying the result by 100 gives us the percentage, which is 7.5%.Rate this question:
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- 18.
Study the following bar-graph and answer the questions given below. The number of Bike A and B type sold over the years in thousand. What is the average number of bikes of A type for all the years together?
- A.
16667
- B.
18667
- C.
25556
- D.
20000
Correct Answer
A. 16667Explanation
The average number of bikes of A type for all the years together is 16667. This can be calculated by adding up the number of bikes of A type sold each year and then dividing by the total number of years.Rate this question:
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- 19.
Study the following bar-graph and answer the questions given below. Number of Bike A and B type sold over the years in thousand. 19. What is the approximate percentage rise in number of bikes of A type from 2005 to 2006?
- A.
200
- B.
300
- C.
400
- D.
500
Correct Answer
C. 400Explanation
The approximate percentage rise in the number of bikes of A type from 2005 to 2006 is 400%.Rate this question:
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- 20.
Study the following bar-graph and answer the questions given below. The number of Bike A and B type sold over the years in thousand. What is the difference between the average of A-type bikes for all the years and the average of B type bikes for all the years?
- A.
8667
- B.
15555
- C.
11111
- D.
None
Correct Answer
D. None -
- 21.
Superconductivity is destroyed.
- A.
At high Tempt
- B.
At high magnetic Fied
- C.
In the Presence of magnetic impurities
- D.
In all of the above
Correct Answer
D. In all of the aboveExplanation
Superconductivity is destroyed in all of the above conditions: at high temperature, at high magnetic field, and in the presence of magnetic impurities. These factors disrupt the delicate balance of electron interactions that allow for superconductivity to occur. High temperatures cause increased thermal energy, which disrupts the formation of Cooper pairs. High magnetic fields can induce a breakdown of the superconducting state by causing the vortices to move and disrupt the flow of supercurrent. Magnetic impurities can scatter the Cooper pairs, leading to a loss of coherence and the destruction of superconductivity.Rate this question:
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- 22.
Bohr Magneton is the unit of?
- A.
Magnetic energy
- B.
Permanent dipole moment due to spin
- C.
Polarisability
- D.
Hysteresis loss
Correct Answer
B. Permanent dipole moment due to spinExplanation
The Bohr Magneton is the unit used to measure the permanent dipole moment due to spin. It is a physical constant that quantifies the magnetic moment of an electron in an atom when it is in motion. The concept of spin refers to the intrinsic angular momentum of a particle, and the permanent dipole moment represents the magnetic field generated by this spin. Therefore, the Bohr Magneton is the appropriate unit for measuring this phenomenon.Rate this question:
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- 23.
For which of the following materials, is the Hall coefficient Zero?
- A.
Metal
- B.
Insulator
- C.
Intrinsic Semiconductor
- D.
Alloy
Correct Answer
A. MetalExplanation
The Hall coefficient is zero for metals because they have a high density of free electrons that can easily move in response to an applied magnetic field. This results in a cancellation of the Hall voltage, leading to a zero Hall coefficient. In contrast, insulators and intrinsic semiconductors have very few free electrons, while alloys can have a mixture of metallic and non-metallic properties, so their Hall coefficients would not be zero.Rate this question:
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- 24.
Bakelite is
- A.
A semiconductor
- B.
Incombustible
- C.
Low resistance conductor
- D.
Highly inflammable
Correct Answer
B. IncombustibleExplanation
Bakelite is a type of plastic that is known for its high resistance to heat and fire. It is made by combining phenol and formaldehyde, which creates a strong and durable material. Due to its chemical composition, Bakelite does not easily catch fire or burn, making it incombustible. This property makes Bakelite suitable for various applications where fire resistance is required, such as electrical insulators and automotive components.Rate this question:
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- 25.
Which one of the Following components is an essential of electromechanical relays?
- A.
Graphite rod
- B.
LED
- C.
An elctromagnet
- D.
MOSFET
Correct Answer
C. An elctromagnetExplanation
An electromagnet is an essential component of electromechanical relays because it is responsible for creating the magnetic field that controls the switching mechanism of the relay. When a current flows through the coil of the electromagnet, it generates a magnetic field that attracts or repels the movable contacts, causing them to open or close the circuit. This allows the relay to control the flow of electricity in a circuit, making it an essential part of the relay's operation.Rate this question:
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- 26.
In integrated circuit , the layer provides
- A.
Electrical connection to external circuit
- B.
Physical Strength
- C.
Isolation
- D.
Conducting path
Correct Answer
C. IsolationExplanation
In an integrated circuit, the isolation layer provides a barrier between different components and circuits on the chip. This layer prevents electrical interference and leakage between these components, ensuring that they operate independently and accurately. It helps to isolate different parts of the circuit from each other and maintain the integrity of the signals being processed.Rate this question:
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- 27.
Ferrites have:
- A.
Low Copper loss
- B.
Low Eddy Current Loss
- C.
Low resistivity
- D.
High Specific gravity in compared to iron
Correct Answer
C. Low resistivityExplanation
Ferrites have low resistivity because they are ceramic materials made from a combination of iron oxide and other metal oxides. These oxides create a crystal structure that restricts the movement of electrons, resulting in low electrical conductivity. This low resistivity is advantageous in applications where high electrical resistance is desired, such as in transformers and inductors.Rate this question:
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- 28.
In a dielectric, the power loss is proportional to:
- A.
![Prasar Bharati Online Exam: Quiz! - Quiz]()
- B.
![Prasar Bharati Online Exam: Quiz! - Quiz]()
- C.
1/
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- D.
1/
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Correct Answer
A.Explanation
In a dielectric, the power loss is proportional to the square of the frequency of the applied electric field. This is because the power loss is caused by the energy dissipation due to the movement of charges within the dielectric material. As the frequency of the applied electric field increases, the charges within the dielectric material experience more frequent changes in direction, leading to increased energy dissipation and power loss. Therefore, the power loss is directly proportional to the square of the frequency.Rate this question:
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- 29.
Bohr Magneton is defined as:
- A.
Magnetic moment of a nucleus spin
- B.
Magnetic moment of an electron spin
- C.
Magnetic moment of an electron orbital motion
- D.
None of these
Correct Answer
B. Magnetic moment of an electron spinExplanation
The Bohr Magneton is defined as the magnetic moment of an electron spin. It represents the quantum mechanical property of an electron's intrinsic angular momentum and its associated magnetic field. The concept of electron spin was introduced by Wolfgang Pauli to explain certain phenomena in atomic physics. The Bohr Magneton is a fundamental constant that quantifies the strength of the magnetic moment associated with an electron's spin.Rate this question:
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- 30.
Dielectric loss in ferrites is:
- A.
Very low
- B.
Very high
- C.
Zero
- D.
Infinte
Correct Answer
B. Very highExplanation
Dielectric loss in ferrites is very high. Ferrites are a type of ceramic material with high electrical resistivity. They have a high dielectric constant and a high loss tangent, which contributes to their high dielectric loss. This means that when an electric field is applied to a ferrite material, a significant amount of energy is dissipated as heat due to the high dielectric losses. This property makes ferrites useful in applications such as electromagnetic interference (EMI) suppression and microwave devices.Rate this question:
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