Question is ⇒ Which of the following is the abnormal phenomena observed in the ionosphere?, Options are ⇒ (A) Communication link interference, (B) Sun spot cycle, (C) Fading and whistlers, (D) Tides and winds, (E) , Leave your comments or Download question paper.

Question is ⇒ Which of the following is the abnormal phenomena observed in the ionosphere?, Options are ⇒ (A) Communication link interference, (B) Sun spot cycle, (C) Fading and whistlers, (D) Tides and winds, (E) , Leave your comments or Download question paper. Previous question Next question


Q1.	Which of the following is the abnormal phenomena observed in the ionosphere?
A.	Communication link interference [Correct Answer]
B.	Sun spot cycle [Wrong Answer]
C.	Fading and whistlers [Wrong Answer]
D.	Tides and winds [Wrong Answer]
View Answer 1 -1 Explanation:- Answer : A Discuss it below : !! OOPS Login [Click here] is required to post your answer/result Help other students, write article, leave your comments

Previous question Next question

Also Read Similar Questions Below :

⇒ A limiter circuit can be built using a diode and resistance.
TRUE
FALSE

⇒ A series resonant circuit has R = 10 Ω, L = 1 μH and C = 1 mF. If R is increased to 20 Ω the resonant frequency
increases
decreases
remains constant
may increases or decreases

⇒ In a display specified as 600 x 400 the number of pixels across the display screen is
600
400
240000
either (a) or (b)

⇒ A wire is carrying current I. The field intensity H at a distance r from the wire
is directed towards wire
is directed away from wire
is tangential every where to a circle of radius r
none of the above

⇒ Inverters find applications in
HVDC transmission
UPS
variable speed ac drives
all of the above

⇒

Assertion (A): A GTO can be turned on and turned off by gate pulses

Reason (R): A GTO can be turned off by negative gate pulse.

Both A and R are correct and R is correct explanation of A
Both A and R correct but R is not correct explanation of A
A is correct but R is wrong
A is wrong but R is correct

⇒ An n type silicon bar 0.1 cm long and 100 μm² in cross-sectional area has a majority carrier concentration of 5 x 10²⁰/m³ and the carrier mobility is 0.13 m⁰/V-s at 300k. If the charge of an electron is 1.6 x 10^-19 coulomb, then the resistance of the bar is
10⁶ ohm
10⁴ ohm
10^-1 ohm
10^-4 ohm

⇒

Assertion (A): A half wavelength line can be used as a 1 : 1 transformer.

Reason (R): The input impedance of a half wavelength line is equal to load impedance.

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 correct but R is wrong
A is wrong but R is correct

⇒ The function Y = AC + BD + EF is
POS
SOP
Hybrid
none of the above

⇒ The number of protons in germanium atom is
4
16
28
32

⇒ In the following transistor circuit V_BE = 0. 7 V, r_c = 25mV/I_E, and β and the capacitance are very l
-180
-120
-90
-60

⇒ For the BJT shown in figure, β = 50, the value of V_CE
3.13 V
4.24 V
5.18 V
none

⇒ A radar beacon is a small radar set having a receiver, a separate transmitter and an antenna.
TRUE
FALSE

⇒ The advantage of transistor over vacuum tube is
no heat is required
small size and light in weight
very low power consumption
all of the above

⇒ In a line with finite attenuation
power transmission is least efficient when there are no standing waves on the line
power transmission is most efficient when there are no standing waves on line
Load power depends on phase constant
standing waves will always exist on the line

⇒ The pure capacitor connected across an A.C. voltage consumed 20 W. This is due to
the capacitive reactance in ohms
the current flowing in the capacitor
the fused capacitor was a big one
none of the above

⇒ In a thyristor the gate lead is connected to the n layer near the p layer to which anode is connected.
TRUE
FALSE

⇒ A class A chopper has an input voltage of 200 V. T_on = 1.5 ms and T_off = 4.5 ms. The duty cycle, average output voltage and ripple factor respectively are
0.5, 100 V and 1
0.25, 50 V and 3
0.25, 50 V and 1
0.5, 100 V and 3

⇒ L/C has the dimension of
time
capacitance
inductance
resistance

⇒ If W_F is the Fermi level, then in a metal at T = 0
all energy levels above W_F filled, all those below W_F are empty
all energy levels below W_F are filled, all those above W_F are empty
some energy levels, both below and above W_F, are filled
all energy levels below and above W_F are filled

⇒ Which of the following is true as regards telephone systems?
A larger facility carrying a larger load operates less efficiently than a smaller capacity
A larger facility carrying a lesser load operates more efficiently than a smaller capacity
A larger facility carrying a larger load operates more efficiently than a smaller capacity
A smaller capacity carrying a larger load operates more efficiently than a larger capacity

⇒ Atomic and molecular resonance is observed in many substances
at microwave frequencies
at low frequencies
at frequencies used in AM broadcast
at both (b) and (c)

⇒ For a given operating frequency a waveguide has more power handling capacity than a coaxial line.
TRUE
FALSE

⇒ The colour of an object is decided by
the reflected colour
the wavelength transmitted through it
reflected colour for opaque object and wavelength transmitted through it for transparent objects
none of the above

⇒ In van der walls crystals, there exists a high degree of stability of the outer electron shell.
TRUE
FALSE

⇒ A remote control for TV uses
LED in receiver and photodiode in transmitter
LED in transmitter and photodiode in receiver
LED in both transmitter and receiver
Photodiode in both transmitter and receiver

⇒ Which among the following waveforms can be reconstructed from its samples without distort
1 and 2
2 and 3
1 and 3
Only 2

⇒ Consider the following statements: The radar pulse must be flat topped to

allow accurate range measurement
allow good minimum range
prevent frequency changes in magnetron
make the returned echoes easier to distinguish from noise.

Which of the above are correct?
1, 2, 3, 4
1, 2, 3
1, 2
1, 3, 4

⇒ The symbol ! in Java means
logical NOT
logical OR
AND
logical XOR

⇒ The electric field of 2.5 x 10⁷ V/m can give 1 eV energy to condition electron, then in a copper block what will be the mean free path of electron?
5 x 10^-8 m
4 x 10^-7 m
0.4 m
0.5 m