← MES Jr. Grade
Past Questions — 2022
Judicial Review in India is based on :
A)
Due process of law
B)
Procedure established by law
C)
Rule of law
D)
Precedents and conventions
Judicial review in India is primarily based on the constitutional principle of **procedure established by law**, borrowed from the Japanese Constitution and reflected in Article 21. The Indian Constitution allows courts to examine whether laws and executive actions conform to the Constitution.
Why others are incorrect:
- **(a) Due process of law**: This is mainly associated with the U.S. Constitution, not the original Indian constitutional formulation.
- **(c) Rule of law**: It is a broader constitutional doctrine, but not the specific basis asked here.
- **(d) Precedents and conventions**: These guide legal interpretation but are not the constitutional basis of judicial review in India.
Hence, the correct answer is **(b) Procedure established by law**.
SDRs is the currency of :
A)
World Bank
B)
Asian Development Bank
C)
IMF
D)
RBI
SDR stands for Special Drawing Rights. It is an international reserve asset created by the International Monetary Fund (IMF) in 1969 to supplement the official reserves of member countries. Therefore, SDRs are associated with the IMF.
Why others are incorrect: World Bank and Asian Development Bank are development lending institutions, but SDR is not their currency. RBI is India’s central bank and uses the Indian Rupee, not SDR as its own currency.
Who among the following propounded the theory of ‘Drain of Wealth’?
A)
Mahatma Gandhi
B)
Jawaharlal Nehru
C)
Nelson Mandela
D)
Dadabhai Naoroji
The theory of ‘Drain of Wealth’ was propounded by Dadabhai Naoroji. He explained that British rule was draining India’s wealth to Britain through mechanisms like export surplus, salaries of British officials, pensions, and administrative expenses. Mahatma Gandhi and Jawaharlal Nehru were important nationalist leaders but did not originate this theory, and Nelson Mandela was a South African leader unrelated to this concept in Indian economic history.
Which of the following is also known as the ‘Great Circle’?
A)
Tropic of Cancer
B)
Tropic of Capricorn
C)
Equator
D)
Pacific Ring of Fire
A great circle is any circle drawn on a sphere whose center coincides with the center of the sphere. On Earth, the Equator is the most well-known great circle because it divides the Earth into two equal halves: the Northern and Southern Hemispheres.
Why others are incorrect:
- Tropic of Cancer and Tropic of Capricorn are small circles, not great circles, because they do not pass through the Earth's center.
- Pacific Ring of Fire is a volcanic and earthquake belt around the Pacific Ocean, not a circle of latitude.
Therefore, the correct answer is Equator.
Which Indian city has announced a detailed plan to zero out carbon emissions by 2050?
A)
Chandigarh
B)
Mumbai
C)
Chennai
D)
Delhi
Mumbai announced a detailed climate action plan aiming for net-zero (zeroing out carbon emissions) by 2050. This was part of the Brihanmumbai Municipal Corporation's climate action roadmap. Chandigarh, Chennai, and Delhi have taken climate-related measures, but the city specifically noted for announcing a detailed plan to achieve net-zero emissions by 2050 is Mumbai.
The Central Government’s contribution in National Pension Scheme (NPS) was increased from 10% to how much percentage?
A)
11 %
B)
12 %
C)
13 %
D)
14 %
The Central Government increased its contribution to the National Pension System (NPS) for Central Government employees from 10% to 14% of basic pay plus dearness allowance. This was announced to make NPS more beneficial for government employees. Hence, option (d) is correct. The other options 11%, 12%, and 13% are incorrect because the notified increase was specifically to 14%.
The blue revolution is related to :
A)
Meat production
B)
Milk production
C)
Fish production
D)
Fruit production
The Blue Revolution refers to the rapid development and increase in fish production and aquaculture. Therefore, option (c) is correct.
Why others are incorrect:
(a) Meat production is not called Blue Revolution.
(b) Milk production is associated with the White Revolution.
(d) Fruit production is generally linked with horticultural development, not Blue Revolution.
Winner of the women’s singles tennis title at the 2022 Australian Open.
A)
Serena Williams
B)
Danielle Collins
C)
Karolína Plíšková
D)
Ashleigh Barty
The women’s singles title at the 2022 Australian Open was won by Ashleigh Barty. She defeated Danielle Collins in the final. Therefore, option (d) is correct. Serena Williams did not win the event, Karolína Plíšková was not the champion, and Danielle Collins was the runner-up.
The most common method which is used to purify the water is :
A)
De-nitrification
B)
Condensation
C)
Hibernation
D)
Chlorination
Chlorination is the most common method used to purify drinking water because chlorine kills harmful bacteria, viruses, and other microorganisms.
Why the other options are incorrect:
- De-nitrification: removes nitrates from water, but it is not the most common general purification method.
- Condensation: is a process used in distillation, not the usual common method for public water purification.
- Hibernation: is a biological state in animals and has nothing to do with water purification.
Therefore, the correct answer is Chlorination.
COP 27 will take place from 7-18 November 2022 in which of the following countries?
A)
UK
B)
Saudi Arabia
C)
Egypt
D)
Israel
COP27, the 27th Conference of the Parties to the UNFCCC, was held from 7-18 November 2022 in Sharm El-Sheikh, Egypt. Therefore, the correct option is (c) Egypt. The UK hosted COP26 in Glasgow in 2021, while Saudi Arabia and Israel were not the hosts of COP27.
Victor Orban became the prime minister of which of the following countries for the 4th time in a row?
A)
Belarus
B)
Hungary
C)
Finland
D)
Lithuania
Viktor Orbán became the Prime Minister of Hungary for the fourth consecutive time after his party, Fidesz, won the 2022 parliamentary election. Therefore, option (b) is correct. The other countries listed—Belarus, Finland, and Lithuania—did not have Viktor Orbán as their prime minister.
Which year is known as the year of great divide in India’s population history?
A)
1911
B)
1921
C)
1951
D)
1971
The year 1921 is called the 'Year of Great Divide' in India’s demographic history because it marks the point after which India’s population began to increase steadily. Before 1921, population growth was irregular due to high birth and death rates, famines, epidemics, and poor health conditions. In 1921, India recorded a negative growth rate for the first and only time in the census history, and from then onward population growth became continuous. Therefore, option (b) is correct. Options (a), (c), and (d) are not associated with this demographic term.
Dennis Parnell Sullivan has been conferred the :
A)
2022 Governor of the year award
B)
Pritzker Prize 2022
C)
Abel Prize 2022
D)
Templeton Prize 2022
Dennis Parnell Sullivan, an American mathematician, was awarded the Abel Prize 2022 for his groundbreaking contributions to topology, especially in its algebraic, geometric, and dynamical aspects.
Why the other options are incorrect:
- (a) 2022 Governor of the year award: not associated with Dennis Sullivan.
- (b) Pritzker Prize 2022: this is an architecture award.
- (d) Templeton Prize 2022: this is awarded for contributions relating to life’s spiritual dimension, not mathematics.
Therefore, the correct answer is (c) Abel Prize 2022.
In India, the Enforcement Directorate (ED) which is a specialized investigation agency works under which union ministry?
A)
Ministry of Defence
B)
Ministry of External Affairs
C)
Ministry of Finance
D)
Ministry of Public Personnel
The Enforcement Directorate (ED) is a specialized financial investigation agency under the Department of Revenue, which functions under the Union Ministry of Finance. It investigates offences related to money laundering and foreign exchange violations. इसलिए the correct answer is (c) Ministry of Finance. The other options are incorrect because ED does not function under the Ministry of Defence, Ministry of External Affairs, or Ministry of Public Personnel.
In a three phase half-wave rectifier, each diode conducts for a duration of
A)
180o
B)
30o
C)
60o
D)
120o
In a three-phase half-wave rectifier, there are three diodes, each connected to one phase of the three-phase supply. The diodes conduct based on which phase has the highest instantaneous voltage.
1. The three-phase supply voltages are displaced by 120° from each other.
2. A diode will conduct only when its anode voltage is higher than the cathode voltage and higher than the voltages of the other two phases.
3. Each phase voltage remains the most positive for a duration of 120° (specifically, from 30° before its peak to 30° after its peak relative to the zero crossing, or more accurately, from the point where it intersects the previous phase to where it intersects the next phase).
4. Therefore, each diode conducts for exactly 1/3 of the total cycle (360° / 3 = 120°).
Comparison with other options:
- 180° is the conduction angle for diodes in a single-phase full-wave rectifier or a three-phase full-wave bridge rectifier.
- 60° and 30° do not correspond to the standard conduction intervals of a half-wave three-phase configuration.
Which of the following is a non vectored hardware interrupt of 8085?
A)
TRAP
B)
RST 7.5
C)
INTR
D)
All of these
In the 8085 microprocessor, interrupts are categorized into two types: Vectored and Non-Vectored.
1. Vectored Interrupts: These are interrupts where the CPU automatically knows the address of the Interrupt Service Routine (ISR) to jump to. The 8085 has five vectored interrupts: TRAP, RST 7.5, RST 6.5, RST 5.5, and RST 0.
- TRAP is the highest priority non-maskable vectored interrupt.
- RST 7.5 is a maskable vectored interrupt.
2. Non-Vectored Interrupts: These are interrupts where the CPU does not have a predefined address for the ISR. The external device providing the interrupt must provide the address of the ISR on the data bus during the interrupt acknowledge cycle.
- INTR (Interrupt Request) is the only non-vectored hardware interrupt in the 8085. When INTR is activated, the microprocessor responds by issuing an INTA (Interrupt Acknowledge) signal, and the external hardware must then place an instruction (usually a RST n or CALL instruction) on the data bus to tell the CPU where to go.
Therefore, TRAP and RST 7.5 are vectored, making INTR the correct choice.
The disadvantage of FM over AM is that
A)
noise is very high for high frequency signals
B)
larger bandwidth is required
C)
high modulating power is required
D)
high output power is required
To determine the disadvantage of Frequency Modulation (FM) compared to Amplitude Modulation (AM), we must compare their fundamental characteristics:
1. **Bandwidth**: In AM, the bandwidth is simply twice the highest modulating frequency (BW = 2fm). In FM, the bandwidth is determined by Carson's Rule (BW ≈ 2(Δf + fm)), where Δf is the frequency deviation. Because Δf is typically much larger than the modulating frequency to achieve a good signal-to-noise ratio, FM requires a significantly larger bandwidth than AM. This is the primary disadvantage of FM.
2. **Noise (Option a)**: This is incorrect. One of the main advantages of FM over AM is its superior noise immunity. Since noise primarily affects the amplitude of a signal, an FM receiver can use a 'limiter' to clip amplitude variations without losing the frequency-encoded information.
3. **Modulating Power (Option c)**: This is incorrect. The power required for modulation is not the defining disadvantage of FM; rather, it is the complexity of the circuitry.
4. **Output Power (Option d)**: This is incorrect. In FM, the transmitted power remains constant regardless of the modulation index, whereas in AM, the power varies with the modulation depth. FM does not inherently require 'higher' output power to function; it simply uses its power more efficiently to combat noise.
In a single-phase full converter, the output voltage during overlap is equal to :
A)
zero
B)
source voltage
C)
source voltage minus the inductance drop
D)
none of these
In a single-phase full converter (fully controlled bridge), 'overlap' occurs due to the source inductance (L_s). During the overlap period, two thyristors in the same leg (or opposite legs depending on the commutation phase) are conducting simultaneously. Specifically, during the commutation interval, the outgoing thyristor and the incoming thyristor both conduct. Because they are connected in parallel across the AC source during this brief transition, the load is effectively connected directly across the AC source. Therefore, the output voltage during the overlap period is equal to the instantaneous source voltage (v_s).
- Option (a) is incorrect because the voltage does not drop to zero; it follows the source waveform.
- Option (c) is incorrect because the 'inductance drop' typically refers to the voltage drop across the source inductor that causes the delay in commutation, but the net voltage delivered to the load during the overlap period is the source voltage itself.
- Option (d) is incorrect as option (b) is the standard theoretical result for power electronics converters.
A microprocessor with a 12-bit address bus will be able to access :
A)
16 kilobytes of memory
B)
4 kilobytes of memory
C)
8 kilobytes of memory
D)
none of these
Step-by-step calculation:
1. The number of addressable memory locations is determined by the formula 2^n, where 'n' is the number of bits in the address bus.
2. Given n = 12 bits, the total number of locations = 2^12.
3. 2^12 = 4096 locations.
4. In standard microprocessor architecture, each memory location typically stores 1 byte (8 bits) of data.
5. Therefore, the total memory capacity = 4096 bytes.
6. Since 1 kilobyte (KB) = 1024 bytes, we calculate: 4096 / 1024 = 4 KB.
Comparing with options:
- Option (a) 16 KB would require a 14-bit address bus (2^14 = 16384).
- Option (b) 4 KB matches our calculation (2^12 = 4096).
- Option (c) 8 KB would require a 13-bit address bus (2^13 = 8192).
The thermal noise is due to random :
A)
motion of atoms and molecules
B)
motion of free electrons
C)
vibration of atoms about their mean position, inside the conducting medium
D)
none of these
Thermal noise, also known as Johnson-Nyquist noise, is the electronic noise generated by the thermal agitation of the charge carriers (usually free electrons) inside an electrical conductor at finite temperature.
1. **Mechanism**: In a conductor, electrons are in constant, random motion due to thermal energy. Even in the absence of an applied voltage, these random fluctuations in the position and velocity of the free electrons create a small, fluctuating voltage across the terminals of the conductor.
2. **Mathematical Relation**: The root-mean-square (RMS) noise voltage is given by the formula V = sqrt(4kTRB), where k is Boltzmann's constant, T is absolute temperature, R is resistance, and B is bandwidth. This shows that the noise is directly proportional to the temperature (T), confirming it is a thermal effect.
3. **Why other options are incorrect**:
- Option (a) and (c) refer to the motion or vibration of atoms and molecules. While thermal energy does cause atomic vibration (phonons), the electrical noise specifically measured as 'thermal noise' in communication systems is the result of the movement of the *charge carriers* (electrons) which creates the electric current/voltage fluctuations, not the vibration of the neutral atomic nuclei themselves.
Which of the following amplifier operations has the highest efficiency?
A)
Class A amplifier
B)
Class B amplifier
C)
Class C amplifier
D)
None of these
Efficiency in power amplifiers is defined as the ratio of the AC power delivered to the load to the DC power drawn from the supply.
1. **Class A Amplifier**: The transistor conducts for the full 360° of the input cycle. Because it draws current even when there is no input signal, it has the lowest efficiency. The maximum theoretical efficiency for a series-fed Class A amplifier is 25%, and 50% for a transformer-coupled one.
2. **Class B Amplifier**: The transistor conducts for only 180° (half) of the input cycle. This significantly reduces power wastage. The maximum theoretical efficiency is approximately 78.5%.
3. **Class C Amplifier**: The transistor conducts for less than 180° (a small fraction) of the input cycle. Because the conduction angle is very small, the DC power consumption is minimized while the output is maintained using a tuned LC resonant circuit. This allows Class C amplifiers to achieve the highest theoretical efficiency, often exceeding 80% and reaching up to 90% or more.
Comparing the three, Class C is the most efficient, although it introduces significant distortion and is primarily used in RF applications.
In a 3-phase controlled bridge rectifier, with an increase of overlap angle the output DC voltage :
A)
decreases
B)
increases
C)
does not change
D)
depends upon load inductance
In a 3-phase controlled bridge rectifier, the 'overlap angle' (denoted as μ) occurs due to the source inductance (commutation inductance). In an ideal scenario (zero source inductance), the current transfers instantaneously from one thyristor to the next. However, in practical circuits, the source inductance prevents the current from changing instantaneously. During the overlap period, two thyristors in the same group are conducting simultaneously. This creates a short-circuit path across the DC output for a brief duration, effectively averaging the output voltage between the outgoing and incoming phases. The mathematical expression for the average output voltage (Vdc) of a 3-phase fully controlled bridge rectifier considering overlap is: Vdc = (3√3 Vm / π) * [cos(α) - (μ/2π)sin(α)] (approximately, or more precisely involving the integral of the voltage during overlap). As the overlap angle μ increases, the voltage drop across the source inductance increases, which reduces the average DC output voltage. Therefore, an increase in the overlap angle leads to a decrease in the output DC voltage.
Each diode of a 3-phase half-wave diode rectifier conducts for :
A)
60o
B)
120o
C)
180o
D)
90o
In a 3-phase half-wave rectifier, there are three diodes, each connected to one phase of the 3-phase supply. The circuit is designed such that the diode connected to the phase with the highest instantaneous voltage conducts, while the others are reverse-biased.
1. The phase voltages are displaced by 120° from each other.
2. A specific diode starts conducting when its phase voltage becomes the most positive among the three phases. This occurs at 30° relative to the phase's own zero-crossing (or -30° relative to the peak).
3. The diode continues to conduct until the next phase voltage exceeds its own voltage.
4. Since the phases are separated by 120°, each diode conducts for exactly one-third of the total cycle (360° / 3 = 120°).
Therefore, the conduction angle for each diode is 120°.
Comparison with other options:
- 60°: Incorrect; this is not the conduction period for a standard half-wave rectifier.
- 180°: Incorrect; this is the conduction angle for diodes in a single-phase full-wave bridge rectifier.
- 90°: Incorrect; this does not correspond to the symmetry of a 3-phase system.
Turn-on and turn-off times of transistor depend on :
A)
static characteristic
B)
junction capacitances
C)
current gain
D)
voltage injection
The turn-on and turn-off times of a transistor (switching speed) are primarily determined by the time it takes to charge and discharge the internal capacitances of the device. In a Bipolar Junction Transistor (BJT), these are the depletion region capacitances of the emitter-base and collector-base junctions.
1. **Turn-on time**: This involves charging the junction capacitances to the required threshold voltage to move the transistor from the cutoff region to the saturation region.
2. **Turn-off time**: This is dominated by the 'storage time,' which is the time required to remove the excess minority carriers stored in the base region and discharge the junction capacitances to move the transistor from saturation back to cutoff.
Why other options are incorrect:
- **Static characteristics (a)**: These describe the DC behavior (like V-I curves) and do not account for the time-dependent (transient) behavior of the device.
- **Current gain (c)**: While current gain ($\beta$) affects the amount of current flowing, it does not directly dictate the speed of the charging/discharging process of the junctions.
- **Voltage injection (d)**: This is not a standard term used to define the intrinsic switching speed of a transistor; the speed is a property of the device's physical construction and capacitance.
The drawback of FM relative to AM is that :
A)
noise is very high for high modulation frequencies
B)
larger bandwidth is required
C)
higher modulating power is required
D)
higher output power is required
To determine the drawback of Frequency Modulation (FM) relative to Amplitude Modulation (AM), we compare their fundamental characteristics:
1. **Bandwidth**: In AM, the bandwidth is simply twice the highest modulating frequency (BW = 2fm). In FM, the bandwidth is determined by Carson's Rule (BW ≈ 2(Δf + fm)), where Δf is the frequency deviation. Because Δf is typically much larger than the modulating frequency to achieve a good signal-to-noise ratio, FM requires a significantly larger portion of the frequency spectrum than AM. This is the primary technical drawback of FM.
2. **Noise Performance**: FM is actually superior to AM in terms of noise. Most noise (like atmospheric or electrical noise) affects the amplitude of a signal. Since FM carries information in the frequency variations and uses 'limiters' to clip amplitude spikes, it is much more resistant to noise than AM. Therefore, option (a) is incorrect.
3. **Power Requirements**: In FM, the amplitude of the carrier remains constant regardless of the modulation index. This means the transmitted power is constant and does not increase with modulation depth, unlike AM where power increases with the modulation index. Therefore, options (c) and (d) are incorrect as FM does not inherently require 'higher' power to operate; in fact, it is more power-efficient in terms of signal quality.
Conclusion: The trade-off for the superior noise immunity and audio quality of FM is the requirement for a much larger bandwidth.