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High frequency waves are | |
A. | absorbed by F_{2} layer [Wrong Answer] |
B. | affected by solar cycle [Correct Answer] |
C. | reflected by D layer [Wrong Answer] |
D. | none of the above [Wrong Answer] |
View Answer
Explanation:-
Answer : B Discuss it below : !! OOPS Login [Click here] is required to post your answer/result |
Also Read Similar Questions Below :
⇒ The V-i relation for a varistor is
i = kv^{n}
v = ki^{n}
i = kv^{3}
v = ki^{3}
⇒ A Wien bridge oscillator uses
negative feedback
positive feedback
both negative and positive feedback
none of the above
⇒ Magnesium is alloyed with conducting materials for antenna primarily with the purpose of
increasing efficiency
improving radiative power
reducing weight
increasing density
⇒ A point charge of 6 μC is located at the origin, uniform line charge density of 180 nC/m of 8 m length lies along the x axis and a uniform sheet of charge equal to 25 nC/m^{2} of area p x 4^{2} lies in the z = 0 plane. Calculate total electric flux leaving the surface of sphere of 4 m radius centered at origin.
86.97 μC
8.697 nC
8.697 μC
86.97 nC
⇒ A thyristor has maximum allowable junction temperature of 110° C and the ambient temperature is 40°C, If the maximum internal power dissipation is 50 W, the thermal resistance is
2° C/W
1.4° C/W
0.7°C/W
2.2° C/W
⇒ For F_{1} layer the maximum ionic density is 2.3 x 10^{4} electrons per cc. The critical frequency for this layer will be
1.36 MHz
13.6 MHz
136 MHz
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⇒ Which of the following is correct for a driving point functions?
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The real parts of all poles and zeros must be negative or zero
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⇒ Which of the following devices is a 'hot-electron' diode?
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Thomson-Deletion diode
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⇒ When a TTL is driving an CMOS gates it is necessary to ensure that
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⇒ A series R-C circuit with R = 3 Ω and X_{C} = 4 Ω at 50 Hz is supplied with a voltage V = 50 + 141.4 sin 314 t. What is the RMS value of the current flowing through the circuit?
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⇒ In an SCR, the anode current consists of
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high thermal conductivity and low melting point
low thermal conductivity and high melting point
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⇒ The logic realized by the circuit shown in figure belo
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F = B ⊕ C
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T_{t} > T_{r}
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quantising noise can be overcome by companding
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⇒ For the differential equation (D^{3} - D^{2} + D -1) [y(t)] = 0 the root of auxiliary equation
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-j, j, 2
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⇒ In a series ac circuit a voltage of 20 V at 25 Hz causes a current of 0.20 A, while the same voltage at 75 Hz causes a current of 0.12 A. The circuit consists of
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either (a) or (b)
⇒ The main advantage of CC amplifier is
High input impedance and low output impedance
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⇒ Consider the circ
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(C + D)
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⇒ In an op-amp differentiator
the amplitude of output is proportional to rate of change of input
the amplitude of output is proportional to input
output occurs when input is finite and constant
polarity of input and output is the same
⇒ The V-i relation for a varistor is
i = kv^{n}
v = ki^{n}
i = kv^{3}
v = ki^{3}
⇒ A Wien bridge oscillator uses
negative feedback
positive feedback
both negative and positive feedback
none of the above
⇒ Magnesium is alloyed with conducting materials for antenna primarily with the purpose of
increasing efficiency
improving radiative power
reducing weight
increasing density
⇒ A point charge of 6 μC is located at the origin, uniform line charge density of 180 nC/m of 8 m length lies along the x axis and a uniform sheet of charge equal to 25 nC/m^{2} of area p x 4^{2} lies in the z = 0 plane. Calculate total electric flux leaving the surface of sphere of 4 m radius centered at origin.
86.97 μC
8.697 nC
8.697 μC
86.97 nC
⇒ A thyristor has maximum allowable junction temperature of 110° C and the ambient temperature is 40°C, If the maximum internal power dissipation is 50 W, the thermal resistance is
2° C/W
1.4° C/W
0.7°C/W
2.2° C/W
⇒ For F_{1} layer the maximum ionic density is 2.3 x 10^{4} electrons per cc. The critical frequency for this layer will be
1.36 MHz
13.6 MHz
136 MHz
1360 MHz
⇒ Which of the following is correct for a driving point functions?
The real parts of all poles must be negative
The real parts of all poles and zeros must be negative
The real parts of all poles and zeros must be negative or zero
The real parts of all zeros must be negative
⇒ Which of the following devices is a 'hot-electron' diode?
Thermionic tube diode
Schottky-Barrier diode
Thomson-Deletion diode
Thermal electron diode
⇒ In a parallel inverter
each thyristor is turned on twice during each cycle
each thyristor is turned on once during each cycle
each thyristor is turned on either once or twice in each load cycle
each thyristor may be turned on upto four times in each load cycle
⇒ Cross-over distortion behaviour is a characteristic of
class A output stage
class B output stage
class AB output stage
common base output stage
⇒ If the frequency is less than the damped frequency in a series- inverter
the distortion of output voltage waveform is low
the distortion of output voltage waveform is high
the distortion of output voltage may be high or low depending on the load impedance
none of the above
⇒ A transistor with a = 0.9 and I_{CBO} = 10 μA is biased so that I_{BQ} = 90 μA. Then I_{EQ} will be
5.15 mA
5.2 mA
5 mA
990 mA
⇒ When a TTL is driving an CMOS gates it is necessary to ensure that
V_{OL}(for TTL) ≤ V_{IL} (for CMOS) and V_{0H} (for TTL) ≥ VIH (for CMOS)
V_{0L} (for TTL) ≥ V_{IL} (for CMOS)
V_{0H} (for TTL) ≤ V_{IH} (for CMOS)
V_{0L} (for TTL) ≥ V_{IL} (for CMOS) and V_{0H} (for TTL) ≤ VIH (for CMOS)
⇒ A series R-C circuit with R = 3 Ω and X_{C} = 4 Ω at 50 Hz is supplied with a voltage V = 50 + 141.4 sin 314 t. What is the RMS value of the current flowing through the circuit?
0.208333333333333
0.416666666666667
20 A
22-36 A
⇒ In an SCR, the anode current consists of
only holes
only electrons
both electrons and holes
either electrons or holes
⇒ High frequency inductors and capacitors are commonly plated with silver. The main purpose of this is to
reduce dc resistance
reduce ac resistance
increase dc resistance
increase ac resistance
⇒ In FM 'guard band' is provided
to limit upper frequency limit
to limit lower frequency limit
so that there is less adjacent channel interference
to limit transmitted power of a station
⇒ Generally a VCR has
four stationary video heads
two stationary video heads
four rotating video heads
two rotating video heads
⇒ The rating of a transformer to deliver 100 watts of D.C. power to a load under half wave rectifier will be nearly
1 kVA
350 VA
175 VA
108 VA
⇒ The sensor generally used in incremental optical encoder is
LED
LCD
photodiode
either (a) or (b)
⇒ Electrical contact materials used in switches, brushes and relays must possess
high thermal conductivity and high melting point
low thermal conductivity and low melting point
high thermal conductivity and low melting point
low thermal conductivity and high melting point
⇒ Maximum power transfer theorem finds application in
power circuits
distribution circuits
communication circuits
both power and communication circuits
⇒ The logic realized by the circuit shown in figure belo
F = A - C
F = A + C
F = B ⊙ C
F = B ⊕ C
⇒ Self impedance is
same for transmitting (T_{t}) and receiving antenna (T_{r})
T_{t} > T_{r}
T_{r} > T_{t}
no relation
⇒ In Pulse Code Modulation system
large bandwidth is required
quantising noise can be overcome by companding
quantising noise can be reduced by decreasing the number of standard levels
suffers from the disadvantage of its incompatibly with TDM
⇒ For the differential equation (D^{3} - D^{2} + D -1) [y(t)] = 0 the root of auxiliary equation
-j, j, 1
-j, j, 2
1, 2, j
1, 2, -j
⇒ In a series ac circuit a voltage of 20 V at 25 Hz causes a current of 0.20 A, while the same voltage at 75 Hz causes a current of 0.12 A. The circuit consists of
R and C in parallel
R and C in series
R and L in series
either (a) or (b)
⇒ The main advantage of CC amplifier is
High input impedance and low output impedance
Low input impedance and high output impedance
High voltage gain
High current gain
⇒ Consider the circ
0
(C + D)
1
(A + B) + (C + D)
⇒ In an op-amp differentiator
the amplitude of output is proportional to rate of change of input
the amplitude of output is proportional to input
output occurs when input is finite and constant
polarity of input and output is the same