All questions of Analog Circuits for Electronics and Communication Engineering (ECE) Exam
Which gas was probably least abundant in the early atmosphere ?- a)H2O
- b)O2
- c)NH3
- d)CO2
Correct answer is option 'B'. Can you explain this answer?
Which gas was probably least abundant in the early atmosphere ?
a)
H2O
b)
O2
c)
NH3
d)
CO2
|
Suraksha Kamble answered |
Yes ,early atmosphere was reducing type and had no gases like oxygen. Early organisms were anerobic.
The peritubular capillaries of the nephron arise from the :- a)afferent arteriole
- b)efferent arteriole
- c)renal artery
- d)arcuate artery
Correct answer is option 'B'. Can you explain this answer?
The peritubular capillaries of the nephron arise from the :
a)
afferent arteriole
b)
efferent arteriole
c)
renal artery
d)
arcuate artery
|
|
Suraksha Kamble answered |
Yes peritubular capillaries arise from efferent arteriole of glomerular capsule and help in reabsorption of filterate.
In the question a circuit and a waveform for the input voltage is given. The diode in circuit has cutin voltage Vγ = 0. Choose the option for the waveform of output voltage vo 
- a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
In the question a circuit and a waveform for the input voltage is given. The diode in circuit has cutin voltage Vγ = 0. Choose the option for the waveform of output voltage vo
a)
b)
c)
d)
|
Ankit Mukherjee answered |
Diode is off for vi < 5 V. Hence vo = 5 V.
For vi > 5 V, vo = vi .Therefore (D) is correct option.
Rate of breathing is controlled mainly by :- a)CO2 level in blood
- b)pH in blood
- c)O2 level in blood
- d)O2 level in blood and pH in blood
Correct answer is option 'A'. Can you explain this answer?
Rate of breathing is controlled mainly by :
a)
CO2 level in blood
b)
pH in blood
c)
O2 level in blood
d)
O2 level in blood and pH in blood
|
|
Suraksha Kamble answered |
Increase in CO2 level in blood triggers the respiratory center of medulla oblongata to increase the rate of beating.
Hence A is right.
Hence A is right.
During seed germination its store food is mobilized by_______- a)ABA
- b)Cytokinin
- c)Ethylene
- d)Gibberellin
Correct answer is option 'D'. Can you explain this answer?
During seed germination its store food is mobilized by_______
a)
ABA
b)
Cytokinin
c)
Ethylene
d)
Gibberellin
|
|
🇳 🇴 🇲 🇦 🇦 🇳 answered |
Function of Gibberellins -
Internodes elongation
Bolting
Promotes seed germination
Promotes flowing in long day plants and inhibit it in short day plants.
Delay Senescene
Induce parthenocarpy in pome fruits
Break bud and seed dormancy
- wherein
Commercially used to increase yield of malt from barley.
Gibberellins promotes seed germination and secretes enzyme to break stored food in seed
Internodes elongation
Bolting
Promotes seed germination
Promotes flowing in long day plants and inhibit it in short day plants.
Delay Senescene
Induce parthenocarpy in pome fruits
Break bud and seed dormancy
- wherein
Commercially used to increase yield of malt from barley.
Gibberellins promotes seed germination and secretes enzyme to break stored food in seed
In the following compounds, the order of acidity is 
- a)(iii) > (iv) > (i) > (ii)
- b)(i) > (iv) > (iii) > (ii)
- c)(ii) > (i) > (iii) > (iv)
- d)(iv) > (iii) > (i) > (ii)
Correct answer is option 'D'. Can you explain this answer?
In the following compounds, the order of acidity is
a)
(iii) > (iv) > (i) > (ii)
b)
(i) > (iv) > (iii) > (ii)
c)
(ii) > (i) > (iii) > (iv)
d)
(iv) > (iii) > (i) > (ii)
|
|
Prem Darade answered |
-M , -I increases the stability of phenol and +M , + I decreases the stability of phenol
Consider the circuit shown in fig.
The both transistor have parameter as followsVTN = 0.8V, kn' = 30 μA/V2Que: If the width-to-length ratios of M1 and M2 are(W/L)1 = (W/L)2 = 40The output Vo is- a)2.5 V
- b)2.5 V
- c)5 V
- d)0 V
Correct answer is option 'B'. Can you explain this answer?
Consider the circuit shown in fig.
The both transistor have parameter as follows
VTN = 0.8V, kn' = 30 μA/V2
Que: If the width-to-length ratios of M1 and M2 are
(W/L)1 = (W/L)2 = 40
The output Vo is
a)
2.5 V
b)
2.5 V
c)
5 V
d)
0 V
|
Sanvi Kapoor answered |
For both transistor VDS = VGS ,
The LED in the circuit of fig. will be on if vi is
- a) > 10 V
- b)<10 V
- c) > 5 V
- d)< 5 V
Correct answer is option 'C'. Can you explain this answer?
The LED in the circuit of fig. will be on if vi is
a)
> 10 V
b)
<10 V
c)
> 5 V
d)
< 5 V
|
Anjana Khatri answered |
When v+ > 5 V, output will be positive and LED will be on. Hence (C) is correct.
Read the following four statements (1 – 4), find out certain mistakes in two of them. (a) In our stomach lactic acid bacteria play beneficial role by checking growth of disease causing microbes.
(b) Lactic acid bacteria produce acid that coagulates and completely digests the milk protein.
(c) Lactic acid bacteria improves the nutritional quality by increasing the amount of Riboflavin
(d) Lactic acid bacteria require suitable temperature for their multiplication. Which of the two statements having mistakes? - a)Statements (a) and (b)
- b)Statement (a) and (c)
- c)Statement (b) and (c)
- d)Statements (b) and (d)
Correct answer is option 'C'. Can you explain this answer?
Read the following four statements (1 – 4), find out certain mistakes in two of them.
(a) In our stomach lactic acid bacteria play beneficial role by checking growth of disease causing microbes.
(b) Lactic acid bacteria produce acid that coagulates and completely digests the milk protein.
(c) Lactic acid bacteria improves the nutritional quality by increasing the amount of Riboflavin
(d) Lactic acid bacteria require suitable temperature for their multiplication.
(b) Lactic acid bacteria produce acid that coagulates and completely digests the milk protein.
(c) Lactic acid bacteria improves the nutritional quality by increasing the amount of Riboflavin
(d) Lactic acid bacteria require suitable temperature for their multiplication.
Which of the two statements having mistakes?
a)
Statements (a) and (b)
b)
Statement (a) and (c)
c)
Statement (b) and (c)
d)
Statements (b) and (d)
|
Mohit Choudhury answered |
To 4) and select the one that best represents the meaning of the original text:
1) There are many different types of birds, such as eagles, sparrows, and parrots.
2) Birds have wings and feathers, which allow them to fly.
3) Birds are warm-blooded animals that lay eggs and have beaks.
4) Birds are vertebrate animals that belong to the class Aves.
1) There are many different types of birds, such as eagles, sparrows, and parrots.
2) Birds have wings and feathers, which allow them to fly.
3) Birds are warm-blooded animals that lay eggs and have beaks.
4) Birds are vertebrate animals that belong to the class Aves.
Out of the following six statements how many of them are correct?1. Electrostatic precipitator can remove more than 99% of particulate matter
2. According to CPCB particulate size 2.5 or less in diameter are most harmful for human health
3. Catalytic converter reduces emission of poisonous gas
4. Amount of biodegradable inorganic matter in sewage water is estimated by measuring BOD
5. Biomagnification is due to the metabolisation of toxic substance by living organisms
6. Eutrophication is natural aging of lake by nutrient enrichment of its water- a)6
- b)5
- c)4
- d)3
Correct answer is option 'C'. Can you explain this answer?
Out of the following six statements how many of them are correct?
1. Electrostatic precipitator can remove more than 99% of particulate matter
2. According to CPCB particulate size 2.5 or less in diameter are most harmful for human health
3. Catalytic converter reduces emission of poisonous gas
4. Amount of biodegradable inorganic matter in sewage water is estimated by measuring BOD
5. Biomagnification is due to the metabolisation of toxic substance by living organisms
6. Eutrophication is natural aging of lake by nutrient enrichment of its water
2. According to CPCB particulate size 2.5 or less in diameter are most harmful for human health
3. Catalytic converter reduces emission of poisonous gas
4. Amount of biodegradable inorganic matter in sewage water is estimated by measuring BOD
5. Biomagnification is due to the metabolisation of toxic substance by living organisms
6. Eutrophication is natural aging of lake by nutrient enrichment of its water
a)
6
b)
5
c)
4
d)
3
|
|
Gopikas S answered |
Option (1),(2),(3),(6) is correct.
incorrect options are (4),(5).
*(4)-Amount of biodegradable organic matter in sewage is estimated by measuring BOD.
*(5)- BIOMAGNIFICATION :
A few toxic substances often present in industrial waste water can undergo biological magnification in the aquatic food chain. It refers to increase in concentration of toxitant at successive tropic levels.
In biomagnification the toxic substances are cannot be metabolised or excreted.
incorrect options are (4),(5).
*(4)-Amount of biodegradable organic matter in sewage is estimated by measuring BOD.
*(5)- BIOMAGNIFICATION :
A few toxic substances often present in industrial waste water can undergo biological magnification in the aquatic food chain. It refers to increase in concentration of toxitant at successive tropic levels.
In biomagnification the toxic substances are cannot be metabolised or excreted.
The theoretical maximum efficiency of a bridge rectifier circuit is- a)48.2%
- b)40.53%
- c)81.06%
- d)82%
Correct answer is option 'C'. Can you explain this answer?
The theoretical maximum efficiency of a bridge rectifier circuit is
a)
48.2%
b)
40.53%
c)
81.06%
d)
82%
|
Aarya Basu answered |
Bridge Rectifier Circuit Efficiency
The bridge rectifier circuit is a widely used circuit that converts AC voltage into DC voltage. The efficiency of a rectifier circuit is the ratio of DC output power to the AC input power. The theoretical maximum efficiency of a bridge rectifier circuit can be calculated by assuming ideal diodes and no voltage drops in the circuit.
Calculation of Maximum Efficiency
The bridge rectifier circuit consists of four diodes that are arranged in a bridge configuration. The AC voltage is applied to the input of the circuit and the output voltage is taken across the load resistor. The maximum efficiency of the circuit can be calculated as follows:
Efficiency, η = (DC output power / AC input power) x 100%
DC output power = (Vdc2 / (2R))
where Vdc = maximum DC voltage across the load resistor and R = load resistor
AC input power = (Vrms2 / R)
where Vrms = RMS voltage of the AC input voltage
Substituting the above equations in the efficiency equation, we get:
η = (Vdc2 / (2R)) / (Vrms2 / R) x 100%
η = (Vdc2 / (2Vrms2)) x 100%
In an ideal bridge rectifier circuit, the maximum DC voltage across the load resistor is equal to the peak voltage of the AC input, which is Vp = √2 x Vrms. Substituting this value in the above equation, we get:
η = (Vp / (2Vrms))2 x 100%
η = (0.5)2 x 100%
η = 25%
However, in a practical circuit, there are voltage drops across the diodes, which reduces the maximum DC voltage across the load resistor. This reduces the efficiency of the circuit. The practical maximum efficiency of a bridge rectifier circuit is around 81.06%.
Therefore, the correct option is (c) 81.06%.
The bridge rectifier circuit is a widely used circuit that converts AC voltage into DC voltage. The efficiency of a rectifier circuit is the ratio of DC output power to the AC input power. The theoretical maximum efficiency of a bridge rectifier circuit can be calculated by assuming ideal diodes and no voltage drops in the circuit.
Calculation of Maximum Efficiency
The bridge rectifier circuit consists of four diodes that are arranged in a bridge configuration. The AC voltage is applied to the input of the circuit and the output voltage is taken across the load resistor. The maximum efficiency of the circuit can be calculated as follows:
Efficiency, η = (DC output power / AC input power) x 100%
DC output power = (Vdc2 / (2R))
where Vdc = maximum DC voltage across the load resistor and R = load resistor
AC input power = (Vrms2 / R)
where Vrms = RMS voltage of the AC input voltage
Substituting the above equations in the efficiency equation, we get:
η = (Vdc2 / (2R)) / (Vrms2 / R) x 100%
η = (Vdc2 / (2Vrms2)) x 100%
In an ideal bridge rectifier circuit, the maximum DC voltage across the load resistor is equal to the peak voltage of the AC input, which is Vp = √2 x Vrms. Substituting this value in the above equation, we get:
η = (Vp / (2Vrms))2 x 100%
η = (0.5)2 x 100%
η = 25%
However, in a practical circuit, there are voltage drops across the diodes, which reduces the maximum DC voltage across the load resistor. This reduces the efficiency of the circuit. The practical maximum efficiency of a bridge rectifier circuit is around 81.06%.
Therefore, the correct option is (c) 81.06%.
The secondary transformer voltage of the rectifier circuit shown in fig. is vs = 60 sin 2π 60tV. Each diode has a cut in voltage of Vγ = 0.6 V. The ripple voltage is to be no more than Vrip = 2 V. The value of filter capacitor will be
- a)48.8 μF
- b)24.4 μF
- c)32.2 μF
- d)16.1 μF
Correct answer is option 'B'. Can you explain this answer?
The secondary transformer voltage of the rectifier circuit shown in fig. is vs = 60 sin 2π 60tV. Each diode has a cut in voltage of Vγ = 0.6 V. The ripple voltage is to be no more than Vrip = 2 V. The value of filter capacitor will be
a)
48.8 μF
b)
24.4 μF
c)
32.2 μF
d)
16.1 μF
|
Zoya Sharma answered |
vs = 60 sin 2π 60tV
A body of mass 10 kg lies on a rough horizontal surface. When a horizontal force of F newtons acts on it, it gets an acceleration of 5 m−s⁻2. And when the horizontal force is doubled, it gets an acceleration of 18 m−s⁻2. The coefficient of friction between the body and the horizontal surface is (Take g = 10 m−s⁻2)- a)0.2
- b)0.4
- c)0.6
- d)0.8
Correct answer is option 'D'. Can you explain this answer?
A body of mass 10 kg lies on a rough horizontal surface. When a horizontal force of F newtons acts on it, it gets an acceleration of 5 m−s⁻2. And when the horizontal force is doubled, it gets an acceleration of 18 m−s⁻2. The coefficient of friction between the body and the horizontal surface is (Take g = 10 m−s⁻2)
a)
0.2
b)
0.4
c)
0.6
d)
0.8
|
|
Sumana Gaddam answered |
The pair of amphoteric hydroxides is- a)Al(OH)₃, LiOH
- b)B(OH)₃,Be(OH)₂
- c)Be(OH)₂,Mg(OH)₂
- d)Be(OH)₂,Zn(OH)₂
Correct answer is option 'D'. Can you explain this answer?
The pair of amphoteric hydroxides is
a)
Al(OH)₃, LiOH
b)
B(OH)₃,Be(OH)₂
c)
Be(OH)₂,Mg(OH)₂
d)
Be(OH)₂,Zn(OH)₂
|
|
Afifa Aaliya answered |
Beryllium hydroxide and zinc hydroxide are atmospheric in nature because they react with both acid and base.
So option " D " island correct answer.
So option " D " island correct answer.
The ‘Pinch-off’ voltage of a JFET is 4 V. Then the off gate voltage of JFET is- a)4V
- b)2.5 V
- c)2 V
- d)1 V
Correct answer is option 'A'. Can you explain this answer?
The ‘Pinch-off’ voltage of a JFET is 4 V. Then the off gate voltage of JFET is
a)
4V
b)
2.5 V
c)
2 V
d)
1 V
|
Neha Basak answered |
The Cut off gate voltage is also known as pinch off voltage at which the drain current becomes zero.
If ‘V’ is the voltage phasor and ‘I’ is the current phasor, then VI represents- a)Apparent power
- b)Active power
- c)Reactive power
- d)Total power
Correct answer is option 'A'. Can you explain this answer?
If ‘V’ is the voltage phasor and ‘I’ is the current phasor, then VI represents
a)
Apparent power
b)
Active power
c)
Reactive power
d)
Total power
|
|
Sarita Yadav answered |
Apparent Power (S): It is defined as the product of r.m.s value of voltage (V) and current (1). It is denoted by S. S = V/I Volt Ampere
The reverse leakage current of the transistor when connected in CB Configuration is 0.3 μ A and it is 18 μA when the same transistor is connected in CE Configuration the value of α and β of the transistor for a base current of 40 mA will be respected.- a)0.912 and 79
- b)0.983 and 59
- c)0.887 and 89
- d)0.983 and 89
Correct answer is option 'B'. Can you explain this answer?
The reverse leakage current of the transistor when connected in CB Configuration is 0.3 μ A and it is 18 μA when the same transistor is connected in CE Configuration the value of α and β of the transistor for a base current of 40 mA will be respected.
a)
0.912 and 79
b)
0.983 and 59
c)
0.887 and 89
d)
0.983 and 89
|
Moumita Chopra answered |
Hence α = 0.983 and β = 59
For the amplifier shown below, the drain current changes from 5 mA to 7 mA when the gate voltage D changed from -4.0 V to -3.7 V. The voltage gain of the amplifier is _____
Correct answer is between '-21,19'. Can you explain this answer?
For the amplifier shown below, the drain current changes from 5 mA to 7 mA when the gate voltage D changed from -4.0 V to -3.7 V. The voltage gain of the amplifier is _____
|
Mrinalini Chavan answered |
The gain of the amplifier is given by:
Av = - gmrD
gm: trans conductance of transistor
rD: effective AC resistance seen by drain terminal
gm = 6.66 ms
rD = RD||RL = 6k||6k = 3 kΩ
Av = -6.66 × 10-3 × 3 × 103
Av = -19.98 ≈ 20
The fish Lepidosiren belongs to the country :- a)South Africa
- b)New Zealand
- c)South America
- d)England
Correct answer is option 'C'. Can you explain this answer?
The fish Lepidosiren belongs to the country :
a)
South Africa
b)
New Zealand
c)
South America
d)
England
|
|
Ramesh Chand answered |
Lepidosiren paradoxa is also called the South American lungfish. It is a freshwater and single species of the lungfish found in swamps and slows moving waters of Amazon, Parguay and lower Parona river basins in South America. They burrow into mud during the dry season. Thus, the correct answer is option'C'.
Plants that act as indicators of SO pollution in the atmosphere are- a)Mosses
- b)Liverworts
- c)Orchids
- d)Epiphytic lichens
Correct answer is option 'D'. Can you explain this answer?
Plants that act as indicators of SO pollution in the atmosphere are
a)
Mosses
b)
Liverworts
c)
Orchids
d)
Epiphytic lichens
|
|
Shatabdi Malik answered |
Lichens are the association of algae nd fungi. They are sensitive to SO2 i. e. will not grow in its presence. These are called pollution indicators they don't grow in polluted areas.
In the above monostable multivibrator circuit above given C = 10 nF. If the frequency of output pulse is 100 kHz the resistor value is _________ kΩ
Correct answer is between '0.8,0.94'. Can you explain this answer?
In the above monostable multivibrator circuit above given C = 10 nF. If the frequency of output pulse is 100 kHz the resistor value is _________ kΩ
|
|
Mrinalini Chavan answered |
The pulse duration in mono-stable multivibrator using 555 timer is T = RC In3
10-5 = 1.1 × R × 10 × 10-9
R = 909.1 Ω
≃ 0.91 kΩ
The nominal quiescent collector current of a transistor is 1.2 mA. If the range of β for this transistor is 80 ≤ β ≤ 120 and if the quiescent collector current changes by +-10 percent, the range in value for rπ is- a)1.73 kΩ < rπ < 2.59 kΩ
- b)1.93 kΩ < rπ < 2.59 kΩ
- c)1.73 kΩ < rπ < 2.59 kΩ
- d)1.56 kΩ < rπ < 2.88 kΩ
Correct answer is option 'D'. Can you explain this answer?
The nominal quiescent collector current of a transistor is 1.2 mA. If the range of β for this transistor is 80 ≤ β ≤ 120 and if the quiescent collector current changes by +-10 percent, the range in value for rπ is
a)
1.73 kΩ < rπ < 2.59 kΩ
b)
1.93 kΩ < rπ < 2.59 kΩ
c)
1.73 kΩ < rπ < 2.59 kΩ
d)
1.56 kΩ < rπ < 2.88 kΩ
|
Navya Sarkar answered |
Which of the following is not readily absorbed in the small intestine?- a)Na+
- b)Cl-
- c)K+
- d)Mg2+
Correct answer is option 'D'. Can you explain this answer?
Which of the following is not readily absorbed in the small intestine?
a)
Na+
b)
Cl-
c)
K+
d)
Mg2+
|
Prince Yasser answered |
Because mg requires specific carrier system to be absorbed by the intestinal cells.about 50% of dietary mg is normally absorbed.
The circuit shown in fig. is at steady state before the switch opens at t = 0. The vc(t) for t > 0 is
- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
The circuit shown in fig. is at steady state before the switch opens at t = 0. The vc(t) for t > 0 is
a)
b)
c)
d)
|
|
Anjana Khatri answered |
For t > 0 the equivalent circuit is shown in fig.
A half wave rectifier is used to supply 24 V DC to a resistive load of 500 Ω and the diode has a forward resistance of 50 Ω. What is the maximum value of the AC voltage required at the input?- a)82.94 V
- b)66.67 V
- c)94.80 V
- d)none of these
Correct answer is option 'A'. Can you explain this answer?
A half wave rectifier is used to supply 24 V DC to a resistive load of 500 Ω and the diode has a forward resistance of 50 Ω. What is the maximum value of the AC voltage required at the input?
a)
82.94 V
b)
66.67 V
c)
94.80 V
d)
none of these
|
|
Sushant Mukherjee answered |
Average value of load current,
Maximum value of load current,
Therefore, maximum AC voltage required at the input is
Maximum value of load current,
Therefore, maximum AC voltage required at the input is
Two RC coupled amplifiers are connected to form a 2-stage amplifier. If the lower and upper cut off frequencies of each individual amplifiers is 100 Hz and 20 kHz. Then the 3-dB bandwidth of the two-state amplifier is ____ Hz.
Correct answer is between '12700,12720'. Can you explain this answer?
Two RC coupled amplifiers are connected to form a 2-stage amplifier. If the lower and upper cut off frequencies of each individual amplifiers is 100 Hz and 20 kHz. Then the 3-dB bandwidth of the two-state amplifier is ____ Hz.
|
|
Navya Sarkar answered |
Concept:
For multistage amplifier consisting of n identical amplifying states, the lower cut off fL (multi) is expressed as
Where f1 = lower cut off frequency of individual state.
Upper cut off frequency is given by:
= 20 × 0.643
= 12.87 kHz
Bandwidth =
= 12714.6 Hz.
In IVF technique, fusion of ovum and sperm occurs in:- a)Fallopian tube
- b)Uterus
- c)Vagina
- d)Culture medium
Correct answer is option 'D'. Can you explain this answer?
In IVF technique, fusion of ovum and sperm occurs in:
a)
Fallopian tube
b)
Uterus
c)
Vagina
d)
Culture medium
|
|
Anuradha Thakare answered |
Here IVF stands for in vitro fertilization so it will occur outside the body i.e in culture medium.
A half-wave rectifier is used to charge a 12V battery through a resistance ‘R’. The input transformer is fed with 34 AC with turns ration 2 : 1. The conduction period of the diode is- a)136°
- b)120°
- c)173°
- d)137°
Correct answer is option 'B'. Can you explain this answer?
A half-wave rectifier is used to charge a 12V battery through a resistance ‘R’. The input transformer is fed with 34 AC with turns ration 2 : 1. The conduction period of the diode is
a)
136°
b)
120°
c)
173°
d)
137°
|
Ishita Patel answered |
Voltage at secondary winding of the coil is Vs
Voltage across diode
Vp → Vs max
Vn → 12 V
For conduction:
Vp > Vn
Therefore the diode is conducting for the period.
Therefore the diode is conducting for the period.
The electron of H-atom transits from n = 1 to n = 4 by absorbing energy. If the energy of n = 1 state is – 21.8 × 10-19 Joule then its energy in n = 4 state will be :- a)– 21.8 × 10-19 Joule
- b)– 5.45 × 10-19 Joule
- c)– 2.725 × 10-19 Joule
- d)– 1.362 × 10-19 Joule
Correct answer is option 'D'. Can you explain this answer?
The electron of H-atom transits from n = 1 to n = 4 by absorbing energy. If the energy of n = 1 state is – 21.8 × 10-19 Joule then its energy in n = 4 state will be :
a)
– 21.8 × 10-19 Joule
b)
– 5.45 × 10-19 Joule
c)
– 2.725 × 10-19 Joule
d)
– 1.362 × 10-19 Joule
|
|
Swara Dey answered |
-13.6 eV, then the energy required to excite the electron to n = 4 state can be calculated using the formula:
En = -13.6 eV/n^2
For n = 1, En = -13.6 eV/1^2 = -13.6 eV
For n = 4, En = -13.6 eV/4^2 = -0.85 eV
The energy required to excite the electron from n = 1 to n = 4 is the difference between the energies of these two states:
ΔE = En - E1 = (-0.85 eV) - (-13.6 eV) = 12.75 eV
Therefore, the energy required to excite the electron from n = 1 to n = 4 is 12.75 eV.
En = -13.6 eV/n^2
For n = 1, En = -13.6 eV/1^2 = -13.6 eV
For n = 4, En = -13.6 eV/4^2 = -0.85 eV
The energy required to excite the electron from n = 1 to n = 4 is the difference between the energies of these two states:
ΔE = En - E1 = (-0.85 eV) - (-13.6 eV) = 12.75 eV
Therefore, the energy required to excite the electron from n = 1 to n = 4 is 12.75 eV.
The Q-point for the Zener diode in fig. is
- a)(0.34 mA, 4 V)
- b)(0.34 mA, 4.93 V)
- c)(0.94 mA, 4 V)
- d)(0.94 mA, 4.93 V)
Correct answer is option 'A'. Can you explain this answer?
The Q-point for the Zener diode in fig. is
a)
(0.34 mA, 4 V)
b)
(0.34 mA, 4.93 V)
c)
(0.94 mA, 4 V)
d)
(0.94 mA, 4.93 V)
|
Suraj S answered |
Terminal voltage of zener is always its reverse breakdown voltage, and current is equal to the external resistor current
Two waves of same frequency and intensity superimpose with each other in opposite phases, then after superposition the- a)Intensity increarses by 4 times
- b)Intensity increarses by 2 times
- c)Frequency increarses by 4 times
- d)None of these
Correct answer is option 'D'. Can you explain this answer?
Two waves of same frequency and intensity superimpose with each other in opposite phases, then after superposition the
a)
Intensity increarses by 4 times
b)
Intensity increarses by 2 times
c)
Frequency increarses by 4 times
d)
None of these
|
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Muskaan Maqbool answered |
When two waves of same frequency and intensity with opposite phase superimpose there will b destructive interference and intensity will become zero.
An alternating current having peak value 14 A is used to heat a metal wire. To produce the same heating effect, a constant current i can be used where i is- a)14 A
- b)about 20 A
- c)7 A
- d)about 10 A
Correct answer is option 'D'. Can you explain this answer?
An alternating current having peak value 14 A is used to heat a metal wire. To produce the same heating effect, a constant current i can be used where i is
a)
14 A
b)
about 20 A
c)
7 A
d)
about 10 A
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Qamar Rao answered |
Explanation:
Peak value of AC current:
- The peak value of the alternating current (AC) is given as 14 A.
Heating effect of current:
- The heating effect of current is directly proportional to the square of the current flowing through the wire (P ∝ I²).
Constant current for same heating effect:
- To produce the same heating effect as the AC current with a peak value of 14 A, we need to find a constant current (i) that would result in the same power dissipation.
- Since power is proportional to the square of the current, we can equate the power dissipation for the AC current (14 A) to the power dissipation for the constant current (i).
Calculation:
- Peak value of AC current (I_AC) = 14 A
- Constant current (i) for the same heating effect = i
- Equating the power dissipation for both currents:
I_AC² = i²
(14 A)² = i²
196 A² = i²
i ≈ 14 A
Conclusion:
- Therefore, to produce the same heating effect as the alternating current with a peak value of 14 A, a constant current of about 14 A (approximately 10 A) can be used.
Peak value of AC current:
- The peak value of the alternating current (AC) is given as 14 A.
Heating effect of current:
- The heating effect of current is directly proportional to the square of the current flowing through the wire (P ∝ I²).
Constant current for same heating effect:
- To produce the same heating effect as the AC current with a peak value of 14 A, we need to find a constant current (i) that would result in the same power dissipation.
- Since power is proportional to the square of the current, we can equate the power dissipation for the AC current (14 A) to the power dissipation for the constant current (i).
Calculation:
- Peak value of AC current (I_AC) = 14 A
- Constant current (i) for the same heating effect = i
- Equating the power dissipation for both currents:
I_AC² = i²
(14 A)² = i²
196 A² = i²
i ≈ 14 A
Conclusion:
- Therefore, to produce the same heating effect as the alternating current with a peak value of 14 A, a constant current of about 14 A (approximately 10 A) can be used.
When the gate-to-source voltage VGS of a MOSFET with a threshold voltage of 400mV, working in saturation is 900mV, the drain current is observed to be 1mA. Neglecting the channel width modulation effect and assuming that the MOSFET is operating at saturation, the drain current for an applied VGS of 1400mV is- a)0.5 mA
- b)2.0 mA
- c)3.5 mA
- d)4.0 mA
Correct answer is option 'D'. Can you explain this answer?
When the gate-to-source voltage VGS of a MOSFET with a threshold voltage of 400mV, working in saturation is 900mV, the drain current is observed to be 1mA. Neglecting the channel width modulation effect and assuming that the MOSFET is operating at saturation, the drain current for an applied VGS of 1400mV is
a)
0.5 mA
b)
2.0 mA
c)
3.5 mA
d)
4.0 mA
|
Mahesh Yadav answered |
The MOSFET current is saturation is given by,
Assertion (A): Bridge arrangement is preferred over centre-tapped transformer arrangement for full-wave rectification.
Reason (R): The bridge arrangement improves the filtering action.- a)Both A and R are true and R is the correct explanation of A.
- b)Both A and R are true but R is not the correct explanation of A.
- c)A is true but R is false.
- d)A is faise but R is true.
Correct answer is option 'C'. Can you explain this answer?
Assertion (A): Bridge arrangement is preferred over centre-tapped transformer arrangement for full-wave rectification.
Reason (R): The bridge arrangement improves the filtering action.
Reason (R): The bridge arrangement improves the filtering action.
a)
Both A and R are true and R is the correct explanation of A.
b)
Both A and R are true but R is not the correct explanation of A.
c)
A is true but R is false.
d)
A is faise but R is true.
|
Pallavi Nair answered |
No filtering action is provided by bridge arrangement. Hence, reason is a false statement.
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