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The ionosphere plays a significant role in radio wave propagation at | |
A. | high frequency [Correct Answer] |
B. | ultra-high frequencies [Wrong Answer] |
C. | microwave frequency [Wrong Answer] |
D. | optical frequencies [Wrong Answer] |
View Answer
Explanation:-
Answer : A Discuss it below : !! OOPS Login [Click here] is required to post your answer/result |
Also Read Similar Questions Below :
⇒ For a stable system having two or more gain crossover frequencies the phase margin is measured at the highest crossover frequency.
TRUE
FALSE
⇒
Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is true, R is false
A is false, R is true
⇒ The current I_{CBO}
increases with increases in temperature
is normally greater for silicon transistor than germanium transistors
mainly depends on the emitter base junction bias
depends largely on the emitter doping
⇒ ROC of sequence x[n] = (3)^{n} ∪[n] + (4)^{n} ∪[- n - 1]
|z| > 4
3 < |z| < 4
|z| < 4
|z| > 3
⇒ The ratio of the directivity of an end fire antenna to that of a broadside antenna is
2
3
4
5
⇒ In modern MOSFET_{S}, the material used for the gate is
high purity silicon
high purity silica
heavily doped polycrystalline silicon
epitaxial grown silicon
⇒ In a practical voltage source, the terminal voltage
cannot be less than source voltage
cannot be higher than source voltage
is always less than source voltage
is always equal to source voltage
⇒ Surface leakage current is a part of
reverse current
forward current
reverse breakdown
forward breakdown
⇒ In a discharging R-L circuit voltage across the resistor exhibits
a linear rise
a linear decay
an exponential growth function
an exponential decay function
⇒ If two network is connected in series-parallel connection then
h = [h_{a}] + [h_{b}]
[a_{a}] + [b_{b}]
[Z] = [Z_{a}] - [Z_{b}]
none
⇒ Bit is
smallest piece of electronic hardware
a drilling tool
an abbreviation for binary digit
the smallest number
⇒ In figure, V_{C} is approximately equa
2 V
4.6 V
8 V
7.6 V
⇒ The current flowing through the resistance R in the circuit in the figure has the form 2 cos 4t, where
(0.18 + j0.72)
(0.46 + j1.90)
- (0.18 + j1.90)
(0.23 - 0.35 j)
⇒ A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is
6 mV
12 mV
24 mV
3 mV
⇒ Which of the following statement about the photo electric emission is incorrect?
The maximum velocity of emission varies with the frequency of incident light
The maximum velocity of emission varies with the intensity of light
The amount of photoelectric emission is directly proportional to the intensity of light
The quantum yield depends on the frequency and not the intensity of incident light
⇒ For a BJT if β = 50, I_{CEO} = 3 μA and I_{C} = 1.2 mA then I_{B}
24 μA
23 μA
20 μA
10 μA
⇒ In a JFET
drain current is very nearly equal to source current
drain current is much less than source current
drain current may be equal to or less than source current
drain current may be even more than source current
⇒ Ferrites are
hard materials
brittle materials
not easily machinable
materials with all above properties
⇒ To ensure that only dominant TE_{10} mode propagates in a rectangular waveguide, the operating frequency
must be more than cutoff frequency of TE_{10} mode
must be less than cutoff frequency of TE_{20} mode
must be more than cutoff frequency of TE_{10} mode and less than cutoff frequency of TE_{20} mode
must be less than cutoff frequency of TE_{10} mode
⇒ Negative feedback in amplifier
reduces gain
increases frequency and phase distortion
reduces bandwidth
increases noise
⇒ The time constant of an R.C. circuit increases if the value of resistance is
increased
decreased
either of the above
none of the above
⇒ V(t) across R_{2} for t > 0 is given
2 - 2e^{-2t}
2 - e^{-2t}
2 - e^{-t}
1 - e^{-t}
⇒ A carrier is modulated by two modulating waves A and B having modulation indices of 0.6 and 0.8 respectively. The overall modulation index is
1
0.7
0.2
1.4
⇒ For the discrete time system of the given fig
y_{k} = 0.5 u_{k - 2} - u_{k} - 0.25 y_{k} - 1
y_{k} = 0.5 u_{k}_{ - 1} - u_{k} - 0.25 y_{k} - 1
y_{k} = 0.5 u_{k} - u_{k}_{ - 1} - 0.25 y_{k} - 1
y_{k} = 0.5 u_{k}_{ - 1} - u_{k}_{ - 1} - 0.25 y_{k} - 1
⇒ Performance of a PIN diode switch is represented by
insertion loss when switch is off
insertion loss when switch is on
insertion loss when switch is on and isolation loss when switch is off
insertion loss when switch is off and isolation loss when switch is on
⇒ In figure, the current I_{410 ∠05 ∠90°5 ∠270°10 ∠90°}
⇒ For a Gaussian process, auto-correlation also implies
statistical dependence
statistical independence
ergodic process
none of the above
⇒ In every practical oscillator, the loop gain is slightly larger than unity and the amplitude of the oscillations is limited by the
magnitude of the loop gain
onset if non-linearity
magnitude of gain of the amplifier
feedback transmission factor
⇒ A noiseless 3 KHz channel can transmit binary at the rate __________ .
12000 bps
10000 bps
6000 bps
3000 bps
⇒ A 1 ms pulse can be converted into a 10 ms pulse by using which one of the following
An astable multivibrator
Stable multivibrator
A bistable multivibrator
A J-K flip-flop
⇒ For a stable system having two or more gain crossover frequencies the phase margin is measured at the highest crossover frequency.
TRUE
FALSE
⇒
Assertion (A): A sweep circuit operates by virtue of recurring transient phenomenon.
Reason (R): Transients are always undesirable.
Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is true, R is false
A is false, R is true
⇒ The current I_{CBO}
increases with increases in temperature
is normally greater for silicon transistor than germanium transistors
mainly depends on the emitter base junction bias
depends largely on the emitter doping
⇒ ROC of sequence x[n] = (3)^{n} ∪[n] + (4)^{n} ∪[- n - 1]
|z| > 4
3 < |z| < 4
|z| < 4
|z| > 3
⇒ The ratio of the directivity of an end fire antenna to that of a broadside antenna is
2
3
4
5
⇒ In modern MOSFET_{S}, the material used for the gate is
high purity silicon
high purity silica
heavily doped polycrystalline silicon
epitaxial grown silicon
⇒ In a practical voltage source, the terminal voltage
cannot be less than source voltage
cannot be higher than source voltage
is always less than source voltage
is always equal to source voltage
⇒ Surface leakage current is a part of
reverse current
forward current
reverse breakdown
forward breakdown
⇒ In a discharging R-L circuit voltage across the resistor exhibits
a linear rise
a linear decay
an exponential growth function
an exponential decay function
⇒ If two network is connected in series-parallel connection then
h = [h_{a}] + [h_{b}]
[a_{a}] + [b_{b}]
[Z] = [Z_{a}] - [Z_{b}]
none
⇒ Bit is
smallest piece of electronic hardware
a drilling tool
an abbreviation for binary digit
the smallest number
⇒ In figure, V_{C} is approximately equa
2 V
4.6 V
8 V
7.6 V
⇒ The current flowing through the resistance R in the circuit in the figure has the form 2 cos 4t, where
(0.18 + j0.72)
(0.46 + j1.90)
- (0.18 + j1.90)
(0.23 - 0.35 j)
⇒ A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is
6 mV
12 mV
24 mV
3 mV
⇒ Which of the following statement about the photo electric emission is incorrect?
The maximum velocity of emission varies with the frequency of incident light
The maximum velocity of emission varies with the intensity of light
The amount of photoelectric emission is directly proportional to the intensity of light
The quantum yield depends on the frequency and not the intensity of incident light
⇒ For a BJT if β = 50, I_{CEO} = 3 μA and I_{C} = 1.2 mA then I_{B}
24 μA
23 μA
20 μA
10 μA
⇒ In a JFET
drain current is very nearly equal to source current
drain current is much less than source current
drain current may be equal to or less than source current
drain current may be even more than source current
⇒ Ferrites are
hard materials
brittle materials
not easily machinable
materials with all above properties
⇒ To ensure that only dominant TE_{10} mode propagates in a rectangular waveguide, the operating frequency
must be more than cutoff frequency of TE_{10} mode
must be less than cutoff frequency of TE_{20} mode
must be more than cutoff frequency of TE_{10} mode and less than cutoff frequency of TE_{20} mode
must be less than cutoff frequency of TE_{10} mode
⇒ Negative feedback in amplifier
reduces gain
increases frequency and phase distortion
reduces bandwidth
increases noise
⇒ The time constant of an R.C. circuit increases if the value of resistance is
increased
decreased
either of the above
none of the above
⇒ V(t) across R_{2} for t > 0 is given
2 - 2e^{-2t}
2 - e^{-2t}
2 - e^{-t}
1 - e^{-t}
⇒ A carrier is modulated by two modulating waves A and B having modulation indices of 0.6 and 0.8 respectively. The overall modulation index is
1
0.7
0.2
1.4
⇒ For the discrete time system of the given fig
y_{k} = 0.5 u_{k - 2} - u_{k} - 0.25 y_{k} - 1
y_{k} = 0.5 u_{k}_{ - 1} - u_{k} - 0.25 y_{k} - 1
y_{k} = 0.5 u_{k} - u_{k}_{ - 1} - 0.25 y_{k} - 1
y_{k} = 0.5 u_{k}_{ - 1} - u_{k}_{ - 1} - 0.25 y_{k} - 1
⇒ Performance of a PIN diode switch is represented by
insertion loss when switch is off
insertion loss when switch is on
insertion loss when switch is on and isolation loss when switch is off
insertion loss when switch is off and isolation loss when switch is on
⇒ In figure, the current I_{410 ∠05 ∠90°5 ∠270°10 ∠90°}
⇒ For a Gaussian process, auto-correlation also implies
statistical dependence
statistical independence
ergodic process
none of the above
⇒ In every practical oscillator, the loop gain is slightly larger than unity and the amplitude of the oscillations is limited by the
magnitude of the loop gain
onset if non-linearity
magnitude of gain of the amplifier
feedback transmission factor
⇒ A noiseless 3 KHz channel can transmit binary at the rate __________ .
12000 bps
10000 bps
6000 bps
3000 bps
⇒ A 1 ms pulse can be converted into a 10 ms pulse by using which one of the following
An astable multivibrator
Stable multivibrator
A bistable multivibrator
A J-K flip-flop